阿里DruidDataSource访问RDS安全级别受限问题排查

客官°小女子只卖身不卖艺 2022-12-08 04:46 277阅读 0赞

**目录**

限制问题日志

错误代码跟踪

异常问题分析

DruidDataSource源码

参考阅读

--------------------

**首先声明：这个锅不是 DruidDataSource的问题，请放心使用 DruidDataSource。**

DS是关系型数据库服务（Relational Database Service）的简称，是一种即开即用、稳定可靠、可弹性伸缩的在线[数据库][Link 1]服务。具有多重安全防护措施和完善的性能监控体系，并提供专业的数据库备份、恢复及优化方案，使您能专注于应用开发和业务发展。

问题描述：使用JDBC和Hikari连接RDS都可以正常启动服务，使用DruidDataSource连接RDS却启动不起来，最后是因为程序授权 license导致服务启动失败，而DruidDataSource的警告异常是系统安全级别的提示而已 。

### 限制问题日志 ###

主要提示的是sun.misc.Unsafe.park(Native method) ，此问题可能是系统级别的安全限制，虽然也有AQS异常，本质上应该涉及到系统Native方法调用。

sun.misc.Unsafe.park(Native Method)
     java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
     java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039)
     com.alibaba.druid.pool.DruidDataSource$CreateConnectionThread.run(DruidDataSource.java:2576)
    17-Sep-2020 18:09:21.112 WARNING [localhost-startStop-1] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [forestar-patrol-ywpt] appears to have started a thread named [Druid-ConnectionPool-Destroy-869651846] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
     java.lang.Thread.sleep(Native Method)
     com.alibaba.druid.pool.DruidDataSource$DestroyConnectionThread.run(DruidDataSource.java:2672)
    17-Sep-2020 18:09:21.113 WARNING [localhost-startStop-1] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [forestar-patrol-ywpt] appears to have started a thread named [fsCacheManager] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
     java.net.SocketInputStream.socketRead0(Native Method)
     java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
     java.net.SocketInputStream.read(SocketInputStream.java:171)
     java.net.SocketInputStream.read(SocketInputStream.java:141)
     java.io.BufferedInputStream.fill(BufferedInputStream.java:246)
     java.io.BufferedInputStream.read1(BufferedInputStream.java:286)
     java.io.BufferedInputStream.read(BufferedInputStream.java:345)
     sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:735)
     sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:678)
     sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1587)
     sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1492)
     net.sf.ehcache.util.UpdateChecker.getUpdateProperties(UpdateChecker.java:106)
     net.sf.ehcache.util.UpdateChecker.doCheck(UpdateChecker.java:70)
     net.sf.ehcache.util.UpdateChecker.checkForUpdate(UpdateChecker.java:60)
     net.sf.ehcache.util.UpdateChecker.run(UpdateChecker.java:51)
     java.util.TimerThread.mainLoop(Timer.java:555)
     java.util.TimerThread.run(Timer.java:505)
    17-Sep-2020 18:09:21.113 WARNING [localhost-startStop-1] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [forestar-patrol-ywpt] appears to have started a thread named [SimplePageCachingFilter.data] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
     sun.misc.Unsafe.park(Native Method)
     java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
     java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
     java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1093)
     java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809)
     java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074)
     java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
     java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
     java.lang.Thread.run(Thread.java:748)
    17-Sep-2020 18:09:21.114 WARNING [localhost-startStop-1] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [forestar-patrol-ywpt] appears to have started a thread named [MedataCache.data] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
     sun.misc.Unsafe.park(Native Method)
     java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
     java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
     java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1093)
     java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809)
     java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074)
     java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
     java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
     java.lang.Thread.run(Thread.java:748)

### 错误代码跟踪  ###

错误点1：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Jvb255YQ_size_16_color_FFFFFF_t_70][]

错误点2：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Jvb255YQ_size_16_color_FFFFFF_t_70 1][]

### 异常问题分析 ###

错误点1分析：这里是AQS队列阻塞。

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Jvb255YQ_size_16_color_FFFFFF_t_70 2][] 定位到park底层调用的是Native方法：这里就是将线程的进行阻塞的方法。

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Jvb255YQ_size_16_color_FFFFFF_t_70 3][]

setBlocker方法本身是调用本地系统Native硬件方法：

![20200918094215700.png][]

而UNSAFE的方法都是本地硬件Native方法：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Jvb255YQ_size_16_color_FFFFFF_t_70 4][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Jvb255YQ_size_16_color_FFFFFF_t_70 5][]

问题点2是同个线程引发的问题实质上是问题1。

### DruidDataSource源码 ###

阿里Druid项目代码：[https://github.com/alibaba/druid][https_github.com_alibaba_druid]

解决方法参考：[RDS的mysql无法正常连接][RDS_mysql] ，或者更换数据源

/*
     * Copyright 1999-2018 Alibaba Group Holding Ltd.
     *
     * Licensed under the Apache License, Version 2.0 (the "License");
     * you may not use this file except in compliance with the License.
     * You may obtain a copy of the License at
     *
     *      http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing, software
     * distributed under the License is distributed on an "AS IS" BASIS,
     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     * See the License for the specific language governing permissions and
     * limitations under the License.
     */
    package com.alibaba.druid.pool;
    
    import static com.alibaba.druid.util.Utils.getBoolean;
    
    import java.io.Closeable;
    import java.security.AccessController;
    import java.security.PrivilegedAction;
    import java.sql.Connection;
    import java.sql.SQLException;
    import java.sql.Statement;
    import java.util.ArrayList;
    import java.util.Arrays;
    import java.util.Collections;
    import java.util.ConcurrentModificationException;
    import java.util.Date;
    import java.util.HashMap;
    import java.util.Iterator;
    import java.util.LinkedHashMap;
    import java.util.List;
    import java.util.Map;
    import java.util.Properties;
    import java.util.ServiceLoader;
    import java.util.StringTokenizer;
    import java.util.TimeZone;
    import java.util.concurrent.CountDownLatch;
    import java.util.concurrent.Future;
    import java.util.concurrent.ScheduledFuture;
    import java.util.concurrent.ScheduledThreadPoolExecutor;
    import java.util.concurrent.TimeUnit;
    import java.util.concurrent.atomic.AtomicLongFieldUpdater;
    import java.util.concurrent.locks.Lock;
    import java.util.concurrent.locks.ReentrantLock;
    
    import javax.management.JMException;
    import javax.management.MBeanRegistration;
    import javax.management.MBeanServer;
    import javax.management.ObjectName;
    import javax.naming.NamingException;
    import javax.naming.Reference;
    import javax.naming.Referenceable;
    import javax.naming.StringRefAddr;
    import javax.sql.ConnectionEvent;
    import javax.sql.ConnectionEventListener;
    import javax.sql.ConnectionPoolDataSource;
    import javax.sql.PooledConnection;
    
    import com.alibaba.druid.Constants;
    import com.alibaba.druid.TransactionTimeoutException;
    import com.alibaba.druid.VERSION;
    import com.alibaba.druid.filter.AutoLoad;
    import com.alibaba.druid.filter.Filter;
    import com.alibaba.druid.filter.FilterChainImpl;
    import com.alibaba.druid.mock.MockDriver;
    import com.alibaba.druid.pool.DruidPooledPreparedStatement.PreparedStatementKey;
    import com.alibaba.druid.pool.vendor.DB2ExceptionSorter;
    import com.alibaba.druid.pool.vendor.InformixExceptionSorter;
    import com.alibaba.druid.pool.vendor.MSSQLValidConnectionChecker;
    import com.alibaba.druid.pool.vendor.MockExceptionSorter;
    import com.alibaba.druid.pool.vendor.MySqlExceptionSorter;
    import com.alibaba.druid.pool.vendor.MySqlValidConnectionChecker;
    import com.alibaba.druid.pool.vendor.NullExceptionSorter;
    import com.alibaba.druid.pool.vendor.OracleExceptionSorter;
    import com.alibaba.druid.pool.vendor.OracleValidConnectionChecker;
    import com.alibaba.druid.pool.vendor.PGExceptionSorter;
    import com.alibaba.druid.pool.vendor.PGValidConnectionChecker;
    import com.alibaba.druid.pool.vendor.SybaseExceptionSorter;
    import com.alibaba.druid.proxy.DruidDriver;
    import com.alibaba.druid.proxy.jdbc.DataSourceProxyConfig;
    import com.alibaba.druid.proxy.jdbc.TransactionInfo;
    import com.alibaba.druid.sql.ast.SQLStatement;
    import com.alibaba.druid.sql.ast.statement.SQLSelectQuery;
    import com.alibaba.druid.sql.ast.statement.SQLSelectQueryBlock;
    import com.alibaba.druid.sql.ast.statement.SQLSelectStatement;
    import com.alibaba.druid.sql.parser.SQLParserUtils;
    import com.alibaba.druid.sql.parser.SQLStatementParser;
    import com.alibaba.druid.stat.DruidDataSourceStatManager;
    import com.alibaba.druid.stat.JdbcDataSourceStat;
    import com.alibaba.druid.stat.JdbcSqlStat;
    import com.alibaba.druid.stat.JdbcSqlStatValue;
    import com.alibaba.druid.support.logging.Log;
    import com.alibaba.druid.support.logging.LogFactory;
    import com.alibaba.druid.util.JMXUtils;
    import com.alibaba.druid.util.JdbcConstants;
    import com.alibaba.druid.util.JdbcUtils;
    import com.alibaba.druid.util.StringUtils;
    import com.alibaba.druid.util.Utils;
    import com.alibaba.druid.wall.WallFilter;
    import com.alibaba.druid.wall.WallProviderStatValue;
    
    /**
     * @author ljw [ljw2083@alibaba-inc.com]
     * @author wenshao [szujobs@hotmail.com]
     */
    public class DruidDataSource extends DruidAbstractDataSource implements DruidDataSourceMBean, ManagedDataSource, Referenceable, Closeable, Cloneable, ConnectionPoolDataSource, MBeanRegistration {
    
        private final static Log                 LOG                       = LogFactory.getLog(DruidDataSource.class);
        private static final long                serialVersionUID          = 1L;
        // stats
        private volatile long                    recycleErrorCount         = 0L;
        private long                             connectCount              = 0L;
        private long                             closeCount                = 0L;
        private volatile long                    connectErrorCount         = 0L;
        private long                             recycleCount              = 0L;
        private long                             removeAbandonedCount      = 0L;
        private long                             notEmptyWaitCount         = 0L;
        private long                             notEmptySignalCount       = 0L;
        private long                             notEmptyWaitNanos         = 0L;
        private int                              keepAliveCheckCount       = 0;
        private int                              activePeak                = 0;
        private long                             activePeakTime            = 0;
        private int                              poolingPeak               = 0;
        private long                             poolingPeakTime           = 0;
        // store
        private volatile DruidConnectionHolder[] connections;
        private int                              poolingCount              = 0;
        private int                              activeCount               = 0;
        private volatile long                    discardCount              = 0;
        private int                              notEmptyWaitThreadCount   = 0;
        private int                              notEmptyWaitThreadPeak    = 0;
        //
        private DruidConnectionHolder[]          evictConnections;
        private DruidConnectionHolder[]          keepAliveConnections;
    
        // threads
        private volatile ScheduledFuture<?>      destroySchedulerFuture;
        private DestroyTask                      destroyTask;
    
        private volatile Future<?>               createSchedulerFuture;
    
        private CreateConnectionThread           createConnectionThread;
        private DestroyConnectionThread          destroyConnectionThread;
        private LogStatsThread                   logStatsThread;
        private int                              createTaskCount;
    
        private final CountDownLatch             initedLatch               = new CountDownLatch(2);
    
        private volatile boolean                 enable                    = true;
    
        private boolean                          resetStatEnable           = true;
        private volatile long                    resetCount                = 0L;
    
        private String                           initStackTrace;
    
        private volatile boolean                 closing                   = false;
        private volatile boolean                 closed                    = false;
        private long                             closeTimeMillis           = -1L;
    
        protected JdbcDataSourceStat             dataSourceStat;
    
        private boolean                          useGlobalDataSourceStat   = false;
        private boolean                          mbeanRegistered           = false;
        public static ThreadLocal<Long>          waitNanosLocal            = new ThreadLocal<Long>();
        private boolean                          logDifferentThread        = true;
        private volatile boolean                 keepAlive                 = false;
        private boolean                          asyncInit                 = false;
        protected boolean                        killWhenSocketReadTimeout = false;
    
        private static List<Filter>              autoFilters               = null;
        private boolean                          loadSpifilterSkip         = false;
    
        protected static final AtomicLongFieldUpdater<DruidDataSource> recycleErrorCountUpdater
                = AtomicLongFieldUpdater.newUpdater(DruidDataSource.class, "recycleErrorCount");
        protected static final AtomicLongFieldUpdater<DruidDataSource> connectErrorCountUpdater
                = AtomicLongFieldUpdater.newUpdater(DruidDataSource.class, "connectErrorCount");
        protected static final AtomicLongFieldUpdater<DruidDataSource> resetCountUpdater
                = AtomicLongFieldUpdater.newUpdater(DruidDataSource.class, "resetCount");
    
    
        public DruidDataSource(){
            this(false);
        }
    
        public DruidDataSource(boolean fairLock){
            super(fairLock);
    
            configFromPropety(System.getProperties());
        }
    
        public boolean isAsyncInit() {
            return asyncInit;
        }
    
        public void setAsyncInit(boolean asyncInit) {
            this.asyncInit = asyncInit;
        }
    
        public void configFromPropety(Properties properties) {
            {
                String property = properties.getProperty("druid.name");
                if (property != null) {
                    this.setName(property);
                }
            }
            {
                String property = properties.getProperty("druid.url");
                if (property != null) {
                    this.setUrl(property);
                }
            }
            {
                String property = properties.getProperty("druid.username");
                if (property != null) {
                    this.setUsername(property);
                }
            }
            {
                String property = properties.getProperty("druid.password");
                if (property != null) {
                    this.setPassword(property);
                }
            }
            {
                Boolean value = getBoolean(properties, "druid.testWhileIdle");
                if (value != null) {
                    this.testWhileIdle = value;
                }
            }
            {
                Boolean value = getBoolean(properties, "druid.testOnBorrow");
                if (value != null) {
                    this.testOnBorrow = value;
                }
            }
            {
                String property = properties.getProperty("druid.validationQuery");
                if (property != null && property.length() > 0) {
                    this.setValidationQuery(property);
                }
            }
            {
                Boolean value = getBoolean(properties, "druid.useGlobalDataSourceStat");
                if (value != null) {
                    this.setUseGlobalDataSourceStat(value);
                }
            }
            {
                Boolean value = getBoolean(properties, "druid.useGloalDataSourceStat"); // compatible for early versions
                if (value != null) {
                    this.setUseGlobalDataSourceStat(value);
                }
            }
            {
                Boolean value = getBoolean(properties, "druid.asyncInit"); // compatible for early versions
                if (value != null) {
                    this.setAsyncInit(value);
                }
            }
            {
                String property = properties.getProperty("druid.filters");
    
                if (property != null && property.length() > 0) {
                    try {
                        this.setFilters(property);
                    } catch (SQLException e) {
                        LOG.error("setFilters error", e);
                    }
                }
            }
            {
                String property = properties.getProperty(Constants.DRUID_TIME_BETWEEN_LOG_STATS_MILLIS);
                if (property != null && property.length() > 0) {
                    try {
                        long value = Long.parseLong(property);
                        this.setTimeBetweenLogStatsMillis(value);
                    } catch (NumberFormatException e) {
                        LOG.error("illegal property '" + Constants.DRUID_TIME_BETWEEN_LOG_STATS_MILLIS + "'", e);
                    }
                }
            }
            {
                String property = properties.getProperty(Constants.DRUID_STAT_SQL_MAX_SIZE);
                if (property != null && property.length() > 0) {
                    try {
                        int value = Integer.parseInt(property);
                        if (dataSourceStat != null) {
                            dataSourceStat.setMaxSqlSize(value);
                        }
                    } catch (NumberFormatException e) {
                        LOG.error("illegal property '" + Constants.DRUID_STAT_SQL_MAX_SIZE + "'", e);
                    }
                }
            }
            {
                Boolean value = getBoolean(properties, "druid.clearFiltersEnable");
                if (value != null) {
                    this.setClearFiltersEnable(value);
                }
            }
            {
                Boolean value = getBoolean(properties, "druid.resetStatEnable");
                if (value != null) {
                    this.setResetStatEnable(value);
                }
            }
            {
                String property = properties.getProperty("druid.notFullTimeoutRetryCount");
                if (property != null && property.length() > 0) {
                    try {
                        int value = Integer.parseInt(property);
                        this.setNotFullTimeoutRetryCount(value);
                    } catch (NumberFormatException e) {
                        LOG.error("illegal property 'druid.notFullTimeoutRetryCount'", e);
                    }
                }
            }
            {
                String property = properties.getProperty("druid.timeBetweenEvictionRunsMillis");
                if (property != null && property.length() > 0) {
                    try {
                        long value = Long.parseLong(property);
                        this.setTimeBetweenEvictionRunsMillis(value);
                    } catch (NumberFormatException e) {
                        LOG.error("illegal property 'druid.timeBetweenEvictionRunsMillis'", e);
                    }
                }
            }
            {
                String property = properties.getProperty("druid.maxWaitThreadCount");
                if (property != null && property.length() > 0) {
                    try {
                        int value = Integer.parseInt(property);
                        this.setMaxWaitThreadCount(value);
                    } catch (NumberFormatException e) {
                        LOG.error("illegal property 'druid.maxWaitThreadCount'", e);
                    }
                }
            }
            {
                String property = properties.getProperty("druid.maxWait");
                if (property != null && property.length() > 0) {
                    try {
                        int value = Integer.parseInt(property);
                        this.setMaxWait(value);
                    } catch (NumberFormatException e) {
                        LOG.error("illegal property 'druid.maxWait'", e);
                    }
                }
            }
            {
                Boolean value = getBoolean(properties, "druid.failFast");
                if (value != null) {
                    this.setFailFast(value);
                }
            }
            {
                String property = properties.getProperty("druid.phyTimeoutMillis");
                if (property != null && property.length() > 0) {
                    try {
                        long value = Long.parseLong(property);
                        this.setPhyTimeoutMillis(value);
                    } catch (NumberFormatException e) {
                        LOG.error("illegal property 'druid.phyTimeoutMillis'", e);
                    }
                }
            }
            {
                String property = properties.getProperty("druid.phyMaxUseCount");
                if (property != null && property.length() > 0) {
                    try {
                        long value = Long.parseLong(property);
                        this.setPhyMaxUseCount(value);
                    } catch (NumberFormatException e) {
                        LOG.error("illegal property 'druid.phyMaxUseCount'", e);
                    }
                }
            }
            {
                String property = properties.getProperty("druid.minEvictableIdleTimeMillis");
                if (property != null && property.length() > 0) {
                    try {
                        long value = Long.parseLong(property);
                        this.setMinEvictableIdleTimeMillis(value);
                    } catch (NumberFormatException e) {
                        LOG.error("illegal property 'druid.minEvictableIdleTimeMillis'", e);
                    }
                }
            }
            {
                String property = properties.getProperty("druid.maxEvictableIdleTimeMillis");
                if (property != null && property.length() > 0) {
                    try {
                        long value = Long.parseLong(property);
                        this.setMaxEvictableIdleTimeMillis(value);
                    } catch (NumberFormatException e) {
                        LOG.error("illegal property 'druid.maxEvictableIdleTimeMillis'", e);
                    }
                }
            }
            {
                Boolean value = getBoolean(properties, "druid.keepAlive");
                if (value != null) {
                    this.setKeepAlive(value);
                }
            }
            {
                String property = properties.getProperty("druid.keepAliveBetweenTimeMillis");
                if (property != null && property.length() > 0) {
                    try {
                        long value = Long.parseLong(property);
                        this.setKeepAliveBetweenTimeMillis(value);
                    } catch (NumberFormatException e) {
                        LOG.error("illegal property 'druid.keepAliveBetweenTimeMillis'", e);
                    }
                }
            }
            {
                Boolean value = getBoolean(properties, "druid.poolPreparedStatements");
                if (value != null) {
                    this.setPoolPreparedStatements0(value);
                }
            }
            {
                Boolean value = getBoolean(properties, "druid.initVariants");
                if (value != null) {
                    this.setInitVariants(value);
                }
            }
            {
                Boolean value = getBoolean(properties, "druid.initGlobalVariants");
                if (value != null) {
                    this.setInitGlobalVariants(value);
                }
            }
            {
                Boolean value = getBoolean(properties, "druid.useUnfairLock");
                if (value != null) {
                    this.setUseUnfairLock(value);
                }
            }
            {
                String property = properties.getProperty("druid.driverClassName");
                if (property != null) {
                    this.setDriverClassName(property);
                }
            }
            {
                String property = properties.getProperty("druid.initialSize");
                if (property != null && property.length() > 0) {
                    try {
                        int value = Integer.parseInt(property);
                        this.setInitialSize(value);
                    } catch (NumberFormatException e) {
                        LOG.error("illegal property 'druid.initialSize'", e);
                    }
                }
            }
            {
                String property = properties.getProperty("druid.minIdle");
                if (property != null && property.length() > 0) {
                    try {
                        int value = Integer.parseInt(property);
                        this.setMinIdle(value);
                    } catch (NumberFormatException e) {
                        LOG.error("illegal property 'druid.minIdle'", e);
                    }
                }
            }
            {
                String property = properties.getProperty("druid.maxActive");
                if (property != null && property.length() > 0) {
                    try {
                        int value = Integer.parseInt(property);
                        this.setMaxActive(value);
                    } catch (NumberFormatException e) {
                        LOG.error("illegal property 'druid.maxActive'", e);
                    }
                }
            }
            {
                Boolean value = getBoolean(properties, "druid.killWhenSocketReadTimeout");
                if (value != null) {
                    setKillWhenSocketReadTimeout(value);
                }
            }
            {
                String property = properties.getProperty("druid.connectProperties");
                if (property != null) {
                    this.setConnectionProperties(property);
                }
            }
            {
                String property = properties.getProperty("druid.maxPoolPreparedStatementPerConnectionSize");
                if (property != null && property.length() > 0) {
                    try {
                        int value = Integer.parseInt(property);
                        this.setMaxPoolPreparedStatementPerConnectionSize(value);
                    } catch (NumberFormatException e) {
                        LOG.error("illegal property 'druid.maxPoolPreparedStatementPerConnectionSize'", e);
                    }
                }
            }
            {
                String property = properties.getProperty("druid.initConnectionSqls");
                if (property != null && property.length() > 0) {
                    try {
                        StringTokenizer tokenizer = new StringTokenizer(property, ";");
                        setConnectionInitSqls(Collections.list(tokenizer));
                    } catch (NumberFormatException e) {
                        LOG.error("illegal property 'druid.initConnectionSqls'", e);
                    }
                }
            }
            {
                String property = System.getProperty("druid.load.spifilter.skip");
                if (property != null && !"false".equals(property)) {
                    loadSpifilterSkip = true;
                }
            }
        }
    
        public boolean isKillWhenSocketReadTimeout() {
            return killWhenSocketReadTimeout;
        }
    
        public void setKillWhenSocketReadTimeout(boolean killWhenSocketTimeOut) {
            this.killWhenSocketReadTimeout = killWhenSocketTimeOut;
        }
    
        public boolean isUseGlobalDataSourceStat() {
            return useGlobalDataSourceStat;
        }
    
        public void setUseGlobalDataSourceStat(boolean useGlobalDataSourceStat) {
            this.useGlobalDataSourceStat = useGlobalDataSourceStat;
        }
    
        public boolean isKeepAlive() {
            return keepAlive;
        }
    
        public void setKeepAlive(boolean keepAlive) {
            this.keepAlive = keepAlive;
        }
    
        public String getInitStackTrace() {
            return initStackTrace;
        }
    
        public boolean isResetStatEnable() {
            return resetStatEnable;
        }
    
        public void setResetStatEnable(boolean resetStatEnable) {
            this.resetStatEnable = resetStatEnable;
            if (dataSourceStat != null) {
                dataSourceStat.setResetStatEnable(resetStatEnable);
            }
        }
    
        public long getDiscardCount() {
            return discardCount;
        }
    
        public void restart() throws SQLException {
            lock.lock();
            try {
                if (activeCount > 0) {
                    throw new SQLException("can not restart, activeCount not zero. " + activeCount);
                }
                if (LOG.isInfoEnabled()) {
                    LOG.info("{dataSource-" + this.getID() + "} restart");
                }
    
                this.close();
                this.resetStat();
                this.inited = false;
                this.enable = true;
                this.closed = false;
            } finally {
                lock.unlock();
            }
        }
    
        public void resetStat() {
            if (!isResetStatEnable()) {
                return;
            }
    
            lock.lock();
            try {
                connectCount = 0;
                closeCount = 0;
                discardCount = 0;
                recycleCount = 0;
                createCount = 0L;
                directCreateCount = 0;
                destroyCount = 0L;
                removeAbandonedCount = 0;
                notEmptyWaitCount = 0;
                notEmptySignalCount = 0L;
                notEmptyWaitNanos = 0;
    
                activePeak = activeCount;
                activePeakTime = 0;
                poolingPeak = 0;
                createTimespan = 0;
                lastError = null;
                lastErrorTimeMillis = 0;
                lastCreateError = null;
                lastCreateErrorTimeMillis = 0;
            } finally {
                lock.unlock();
            }
    
            connectErrorCountUpdater.set(this, 0);
            errorCountUpdater.set(this, 0);
            commitCountUpdater.set(this, 0);
            rollbackCountUpdater.set(this, 0);
            startTransactionCountUpdater.set(this, 0);
            cachedPreparedStatementHitCountUpdater.set(this, 0);
            closedPreparedStatementCountUpdater.set(this, 0);
            preparedStatementCountUpdater.set(this, 0);
            transactionHistogram.reset();
            cachedPreparedStatementDeleteCountUpdater.set(this, 0);
            recycleErrorCountUpdater.set(this, 0);
    
            resetCountUpdater.incrementAndGet(this);
        }
    
        public long getResetCount() {
            return this.resetCount;
        }
    
        public boolean isEnable() {
            return enable;
        }
    
        public void setEnable(boolean enable) {
            lock.lock();
            try {
                this.enable = enable;
                if (!enable) {
                    notEmpty.signalAll();
                    notEmptySignalCount++;
                }
            } finally {
                lock.unlock();
            }
        }
    
        public void setPoolPreparedStatements(boolean value) {
            setPoolPreparedStatements0(value);
        }
    
        private void setPoolPreparedStatements0(boolean value) {
            if (this.poolPreparedStatements == value) {
                return;
            }
    
            this.poolPreparedStatements = value;
    
            if (!inited) {
                return;
            }
    
            if (LOG.isInfoEnabled()) {
                LOG.info("set poolPreparedStatements " + this.poolPreparedStatements + " -> " + value);
            }
    
            if (!value) {
                lock.lock();
                try {
    
                    for (int i = 0; i < poolingCount; ++i) {
                        DruidConnectionHolder connection = connections[i];
    
                        for (PreparedStatementHolder holder : connection.getStatementPool().getMap().values()) {
                            closePreapredStatement(holder);
                        }
    
                        connection.getStatementPool().getMap().clear();
                    }
                } finally {
                    lock.unlock();
                }
            }
        }
    
        public void setMaxActive(int maxActive) {
            if (this.maxActive == maxActive) {
                return;
            }
    
            if (maxActive == 0) {
                throw new IllegalArgumentException("maxActive can't not set zero");
            }
    
            if (!inited) {
                this.maxActive = maxActive;
                return;
            }
    
            if (maxActive < this.minIdle) {
                throw new IllegalArgumentException("maxActive less than minIdle, " + maxActive + " < " + this.minIdle);
            }
    
            if (LOG.isInfoEnabled()) {
                LOG.info("maxActive changed : " + this.maxActive + " -> " + maxActive);
            }
    
            lock.lock();
            try {
                int allCount = this.poolingCount + this.activeCount;
    
                if (maxActive > allCount) {
                    this.connections = Arrays.copyOf(this.connections, maxActive);
                    evictConnections = new DruidConnectionHolder[maxActive];
                    keepAliveConnections = new DruidConnectionHolder[maxActive];
                } else {
                    this.connections = Arrays.copyOf(this.connections, allCount);
                    evictConnections = new DruidConnectionHolder[allCount];
                    keepAliveConnections = new DruidConnectionHolder[allCount];
                }
    
                this.maxActive = maxActive;
            } finally {
                lock.unlock();
            }
        }
    
        @SuppressWarnings("rawtypes")
        public void setConnectProperties(Properties properties) {
            if (properties == null) {
                properties = new Properties();
            }
    
            boolean equals;
            if (properties.size() == this.connectProperties.size()) {
                equals = true;
                for (Map.Entry entry : properties.entrySet()) {
                    Object value = this.connectProperties.get(entry.getKey());
                    Object entryValue = entry.getValue();
                    if (value == null && entryValue != null) {
                        equals = false;
                        break;
                    }
    
                    if (!value.equals(entry.getValue())) {
                        equals = false;
                        break;
                    }
                }
            } else {
                equals = false;
            }
    
            if (!equals) {
                if (inited && LOG.isInfoEnabled()) {
                    LOG.info("connectProperties changed : " + this.connectProperties + " -> " + properties);
                }
    
                configFromPropety(properties);
    
                for (Filter filter : this.filters) {
                    filter.configFromProperties(properties);
                }
    
                if (exceptionSorter != null) {
                    exceptionSorter.configFromProperties(properties);
                }
    
                if (validConnectionChecker != null) {
                    validConnectionChecker.configFromProperties(properties);
                }
    
                if (statLogger != null) {
                    statLogger.configFromProperties(properties);
                }
            }
    
            this.connectProperties = properties;
        }
    
        public void init() throws SQLException {
            if (inited) {
                return;
            }
    
            // bug fixed for dead lock, for issue #2980
            DruidDriver.getInstance();
    
            final ReentrantLock lock = this.lock;
            try {
                lock.lockInterruptibly();
            } catch (InterruptedException e) {
                throw new SQLException("interrupt", e);
            }
    
            boolean init = false;
            try {
                if (inited) {
                    return;
                }
    
                initStackTrace = Utils.toString(Thread.currentThread().getStackTrace());
    
                this.id = DruidDriver.createDataSourceId();
                if (this.id > 1) {
                    long delta = (this.id - 1) * 100000;
                    this.connectionIdSeedUpdater.addAndGet(this, delta);
                    this.statementIdSeedUpdater.addAndGet(this, delta);
                    this.resultSetIdSeedUpdater.addAndGet(this, delta);
                    this.transactionIdSeedUpdater.addAndGet(this, delta);
                }
    
                if (this.jdbcUrl != null) {
                    this.jdbcUrl = this.jdbcUrl.trim();
                    initFromWrapDriverUrl();
                }
    
                for (Filter filter : filters) {
                    filter.init(this);
                }
    
                if (this.dbType == null || this.dbType.length() == 0) {
                    this.dbType = JdbcUtils.getDbType(jdbcUrl, null);
                }
    
                if (JdbcConstants.MYSQL.equals(this.dbType)
                        || JdbcConstants.MARIADB.equals(this.dbType)
                        || JdbcConstants.ALIYUN_ADS.equals(this.dbType)) {
                    boolean cacheServerConfigurationSet = false;
                    if (this.connectProperties.containsKey("cacheServerConfiguration")) {
                        cacheServerConfigurationSet = true;
                    } else if (this.jdbcUrl.indexOf("cacheServerConfiguration") != -1) {
                        cacheServerConfigurationSet = true;
                    }
                    if (cacheServerConfigurationSet) {
                        this.connectProperties.put("cacheServerConfiguration", "true");
                    }
                }
    
                if (maxActive <= 0) {
                    throw new IllegalArgumentException("illegal maxActive " + maxActive);
                }
    
                if (maxActive < minIdle) {
                    throw new IllegalArgumentException("illegal maxActive " + maxActive);
                }
    
                if (getInitialSize() > maxActive) {
                    throw new IllegalArgumentException("illegal initialSize " + this.initialSize + ", maxActive " + maxActive);
                }
    
                if (timeBetweenLogStatsMillis > 0 && useGlobalDataSourceStat) {
                    throw new IllegalArgumentException("timeBetweenLogStatsMillis not support useGlobalDataSourceStat=true");
                }
    
                if (maxEvictableIdleTimeMillis < minEvictableIdleTimeMillis) {
                    throw new SQLException("maxEvictableIdleTimeMillis must be grater than minEvictableIdleTimeMillis");
                }
    
                if (this.driverClass != null) {
                    this.driverClass = driverClass.trim();
                }
    
                initFromSPIServiceLoader();
    
                if (this.driver == null) {
                    if (this.driverClass == null || this.driverClass.isEmpty()) {
                        this.driverClass = JdbcUtils.getDriverClassName(this.jdbcUrl);
                    }
    
                    if (MockDriver.class.getName().equals(driverClass)) {
                        driver = MockDriver.instance;
                    } else {
                        if (jdbcUrl == null && (driverClass == null || driverClass.length() == 0)) {
                            throw new SQLException("url not set");
                        }
                        driver = JdbcUtils.createDriver(driverClassLoader, driverClass);
                    }
                } else {
                    if (this.driverClass == null) {
                        this.driverClass = driver.getClass().getName();
                    }
                }
    
                initCheck();
    
                initExceptionSorter();
                initValidConnectionChecker();
                validationQueryCheck();
    
                if (isUseGlobalDataSourceStat()) {
                    dataSourceStat = JdbcDataSourceStat.getGlobal();
                    if (dataSourceStat == null) {
                        dataSourceStat = new JdbcDataSourceStat("Global", "Global", this.dbType);
                        JdbcDataSourceStat.setGlobal(dataSourceStat);
                    }
                    if (dataSourceStat.getDbType() == null) {
                        dataSourceStat.setDbType(this.dbType);
                    }
                } else {
                    dataSourceStat = new JdbcDataSourceStat(this.name, this.jdbcUrl, this.dbType, this.connectProperties);
                }
                dataSourceStat.setResetStatEnable(this.resetStatEnable);
    
                connections = new DruidConnectionHolder[maxActive];
                evictConnections = new DruidConnectionHolder[maxActive];
                keepAliveConnections = new DruidConnectionHolder[maxActive];
    
                SQLException connectError = null;
    
                if (createScheduler != null && asyncInit) {
                    for (int i = 0; i < initialSize; ++i) {
                        createTaskCount++;
                        CreateConnectionTask task = new CreateConnectionTask(true);
                        this.createSchedulerFuture = createScheduler.submit(task);
                    }
                } else if (!asyncInit) {
                    // init connections
                    while (poolingCount < initialSize) {
                        try {
                            PhysicalConnectionInfo pyConnectInfo = createPhysicalConnection();
                            DruidConnectionHolder holder = new DruidConnectionHolder(this, pyConnectInfo);
                            connections[poolingCount++] = holder;
                        } catch (SQLException ex) {
                            LOG.error("init datasource error, url: " + this.getUrl(), ex);
                            if (initExceptionThrow) {
                                connectError = ex;
                                break;
                            } else {
                                Thread.sleep(3000);
                            }
                        }
                    }
    
                    if (poolingCount > 0) {
                        poolingPeak = poolingCount;
                        poolingPeakTime = System.currentTimeMillis();
                    }
                }
    
                createAndLogThread();
                createAndStartCreatorThread();
                createAndStartDestroyThread();
    
                initedLatch.await();
                init = true;
    
                initedTime = new Date();
                registerMbean();
    
                if (connectError != null && poolingCount == 0) {
                    throw connectError;
                }
    
                if (keepAlive) {
                    // async fill to minIdle
                    if (createScheduler != null) {
                        for (int i = 0; i < minIdle; ++i) {
                            createTaskCount++;
                            CreateConnectionTask task = new CreateConnectionTask(true);
                            this.createSchedulerFuture = createScheduler.submit(task);
                        }
                    } else {
                        this.emptySignal();
                    }
                }
    
            } catch (SQLException e) {
                LOG.error("{dataSource-" + this.getID() + "} init error", e);
                throw e;
            } catch (InterruptedException e) {
                throw new SQLException(e.getMessage(), e);
            } catch (RuntimeException e){
                LOG.error("{dataSource-" + this.getID() + "} init error", e);
                throw e;
            } catch (Error e){
                LOG.error("{dataSource-" + this.getID() + "} init error", e);
                throw e;
    
            } finally {
                inited = true;
                lock.unlock();
    
                if (init && LOG.isInfoEnabled()) {
                    String msg = "{dataSource-" + this.getID();
    
                    if (this.name != null && !this.name.isEmpty()) {
                        msg += ",";
                        msg += this.name;
                    }
    
                    msg += "} inited";
    
                    LOG.info(msg);
                }
            }
        }
    
        private void createAndLogThread() {
            if (this.timeBetweenLogStatsMillis <= 0) {
                return;
            }
    
            String threadName = "Druid-ConnectionPool-Log-" + System.identityHashCode(this);
            logStatsThread = new LogStatsThread(threadName);
            logStatsThread.start();
    
            this.resetStatEnable = false;
        }
    
        protected void createAndStartDestroyThread() {
            destroyTask = new DestroyTask();
    
            if (destroyScheduler != null) {
                long period = timeBetweenEvictionRunsMillis;
                if (period <= 0) {
                    period = 1000;
                }
                destroySchedulerFuture = destroyScheduler.scheduleAtFixedRate(destroyTask, period, period,
                                                                              TimeUnit.MILLISECONDS);
                initedLatch.countDown();
                return;
            }
    
            String threadName = "Druid-ConnectionPool-Destroy-" + System.identityHashCode(this);
            destroyConnectionThread = new DestroyConnectionThread(threadName);
            destroyConnectionThread.start();
        }
    
        protected void createAndStartCreatorThread() {
            if (createScheduler == null) {
                String threadName = "Druid-ConnectionPool-Create-" + System.identityHashCode(this);
                createConnectionThread = new CreateConnectionThread(threadName);
                createConnectionThread.start();
                return;
            }
    
            initedLatch.countDown();
        }
    
        /**
         * load filters from SPI ServiceLoader
         * 
         * @see ServiceLoader
         */
        private void initFromSPIServiceLoader() {
            if (loadSpifilterSkip) {
                return;
            }
    
            if (autoFilters == null) {
                List<Filter> filters = new ArrayList<Filter>();
                ServiceLoader<Filter> autoFilterLoader = ServiceLoader.load(Filter.class);
    
                for (Filter filter : autoFilterLoader) {
                    AutoLoad autoLoad = filter.getClass().getAnnotation(AutoLoad.class);
                    if (autoLoad != null && autoLoad.value()) {
                        filters.add(filter);
                    }
                }
                autoFilters = filters;
            }
    
            for (Filter filter : autoFilters) {
                if (LOG.isInfoEnabled()) {
                    LOG.info("load filter from spi :" + filter.getClass().getName());
                }
                addFilter(filter);
            }
        }
    
        private void initFromWrapDriverUrl() throws SQLException {
            if (!jdbcUrl.startsWith(DruidDriver.DEFAULT_PREFIX)) {
                return;
            }
    
            DataSourceProxyConfig config = DruidDriver.parseConfig(jdbcUrl, null);
            this.driverClass = config.getRawDriverClassName();
    
            LOG.error("error url : '" + jdbcUrl + "', it should be : '" + config.getRawUrl() + "'");
    
            this.jdbcUrl = config.getRawUrl();
            if (this.name == null) {
                this.name = config.getName();
            }
    
            for (Filter filter : config.getFilters()) {
                addFilter(filter);
            }
        }
    
        /**
         * 会去重复
         * 
         * @param filter
         */
        private void addFilter(Filter filter) {
            boolean exists = false;
            for (Filter initedFilter : this.filters) {
                if (initedFilter.getClass() == filter.getClass()) {
                    exists = true;
                    break;
                }
            }
    
            if (!exists) {
                filter.init(this);
                this.filters.add(filter);
            }
    
        }
    
        private void validationQueryCheck() {
            if (!(testOnBorrow || testOnReturn || testWhileIdle)) {
                return;
            }
    
            if (this.validConnectionChecker != null) {
                return;
            }
    
            if (this.validationQuery != null && this.validationQuery.length() > 0) {
                return;
            }
    
            String errorMessage = "";
    
            if (testOnBorrow) {
                errorMessage += "testOnBorrow is true, ";
            }
    
            if (testOnReturn) {
                errorMessage += "testOnReturn is true, ";
            }
    
            if (testWhileIdle) {
                errorMessage += "testWhileIdle is true, ";
            }
    
            LOG.error(errorMessage + "validationQuery not set");
        }
    
        protected void initCheck() throws SQLException {
            if (JdbcUtils.ORACLE.equals(this.dbType)) {
                isOracle = true;
    
                if (driver.getMajorVersion() < 10) {
                    throw new SQLException("not support oracle driver " + driver.getMajorVersion() + "."
                                           + driver.getMinorVersion());
                }
    
                if (driver.getMajorVersion() == 10 && isUseOracleImplicitCache()) {
                    this.getConnectProperties().setProperty("oracle.jdbc.FreeMemoryOnEnterImplicitCache", "true");
                }
    
                oracleValidationQueryCheck();
            } else if (JdbcUtils.DB2.equals(dbType)) {
                db2ValidationQueryCheck();
            } else if (JdbcUtils.MYSQL.equals(this.dbType)
                    || JdbcUtils.MYSQL_DRIVER_6.equals(this.dbType)) {
                isMySql = true;
            }
    
            if (removeAbandoned) {
                LOG.warn("removeAbandoned is true, not use in productiion.");
            }
        }
    
        private void oracleValidationQueryCheck() {
            if (validationQuery == null) {
                return;
            }
            if (validationQuery.length() == 0) {
                return;
            }
    
            SQLStatementParser sqlStmtParser = SQLParserUtils.createSQLStatementParser(validationQuery, this.dbType);
            List<SQLStatement> stmtList = sqlStmtParser.parseStatementList();
    
            if (stmtList.size() != 1) {
                return;
            }
    
            SQLStatement stmt = stmtList.get(0);
            if (!(stmt instanceof SQLSelectStatement)) {
                return;
            }
    
            SQLSelectQuery query = ((SQLSelectStatement) stmt).getSelect().getQuery();
            if (query instanceof SQLSelectQueryBlock) {
                if (((SQLSelectQueryBlock) query).getFrom() == null) {
                    LOG.error("invalid oracle validationQuery. " + validationQuery + ", may should be : " + validationQuery
                              + " FROM DUAL");
                }
            }
        }
    
        private void db2ValidationQueryCheck() {
            if (validationQuery == null) {
                return;
            }
            if (validationQuery.length() == 0) {
                return;
            }
    
            SQLStatementParser sqlStmtParser = SQLParserUtils.createSQLStatementParser(validationQuery, this.dbType);
            List<SQLStatement> stmtList = sqlStmtParser.parseStatementList();
    
            if (stmtList.size() != 1) {
                return;
            }
    
            SQLStatement stmt = stmtList.get(0);
            if (!(stmt instanceof SQLSelectStatement)) {
                return;
            }
    
            SQLSelectQuery query = ((SQLSelectStatement) stmt).getSelect().getQuery();
            if (query instanceof SQLSelectQueryBlock) {
                if (((SQLSelectQueryBlock) query).getFrom() == null) {
                    LOG.error("invalid db2 validationQuery. " + validationQuery + ", may should be : " + validationQuery
                              + " FROM SYSDUMMY");
                }
            }
        }
    
        private void initValidConnectionChecker() {
            if (this.validConnectionChecker != null) {
                return;
            }
    
            String realDriverClassName = driver.getClass().getName();
            if (JdbcUtils.isMySqlDriver(realDriverClassName)) {
                this.validConnectionChecker = new MySqlValidConnectionChecker();
    
            } else if (realDriverClassName.equals(JdbcConstants.ORACLE_DRIVER)
                    || realDriverClassName.equals(JdbcConstants.ORACLE_DRIVER2)) {
                this.validConnectionChecker = new OracleValidConnectionChecker();
    
            } else if (realDriverClassName.equals(JdbcConstants.SQL_SERVER_DRIVER)
                       || realDriverClassName.equals(JdbcConstants.SQL_SERVER_DRIVER_SQLJDBC4)
                       || realDriverClassName.equals(JdbcConstants.SQL_SERVER_DRIVER_JTDS)) {
                this.validConnectionChecker = new MSSQLValidConnectionChecker();
    
            } else if (realDriverClassName.equals(JdbcConstants.POSTGRESQL_DRIVER)
                    || realDriverClassName.equals(JdbcConstants.ENTERPRISEDB_DRIVER)) {
                this.validConnectionChecker = new PGValidConnectionChecker();
            }
        }
    
        private void initExceptionSorter() {
            if (exceptionSorter instanceof NullExceptionSorter) {
                if (driver instanceof MockDriver) {
                    return;
                }
            } else if (this.exceptionSorter != null) {
                return;
            }
    
    
            for (Class<?> driverClass = driver.getClass();;) {
                String realDriverClassName = driverClass.getName();
                if (realDriverClassName.equals(JdbcConstants.MYSQL_DRIVER) //
                        || realDriverClassName.equals(JdbcConstants.MYSQL_DRIVER_6)) {
                    this.exceptionSorter = new MySqlExceptionSorter();
                    this.isMySql = true;
                } else if (realDriverClassName.equals(JdbcConstants.ORACLE_DRIVER)
                        || realDriverClassName.equals(JdbcConstants.ORACLE_DRIVER2)) {
                    this.exceptionSorter = new OracleExceptionSorter();
                } else if (realDriverClassName.equals("com.informix.jdbc.IfxDriver")) {
                    this.exceptionSorter = new InformixExceptionSorter();
    
                } else if (realDriverClassName.equals("com.sybase.jdbc2.jdbc.SybDriver")) {
                    this.exceptionSorter = new SybaseExceptionSorter();
    
                } else if (realDriverClassName.equals(JdbcConstants.POSTGRESQL_DRIVER)
                        || realDriverClassName.equals(JdbcConstants.ENTERPRISEDB_DRIVER)) {
                    this.exceptionSorter = new PGExceptionSorter();
    
                } else if (realDriverClassName.equals("com.alibaba.druid.mock.MockDriver")) {
                    this.exceptionSorter = new MockExceptionSorter();
                } else if (realDriverClassName.contains("DB2")) {
                    this.exceptionSorter = new DB2ExceptionSorter();
    
                } else {
                    Class<?> superClass = driverClass.getSuperclass();
                    if (superClass != null && superClass != Object.class) {
                        driverClass = superClass;
                        continue;
                    }
                }
    
                break;
            }
        }
    
        @Override
        public DruidPooledConnection getConnection() throws SQLException {
            return getConnection(maxWait);
        }
    
        public DruidPooledConnection getConnection(long maxWaitMillis) throws SQLException {
            init();
    
            if (filters.size() > 0) {
                FilterChainImpl filterChain = new FilterChainImpl(this);
                return filterChain.dataSource_connect(this, maxWaitMillis);
            } else {
                return getConnectionDirect(maxWaitMillis);
            }
        }
    
        @Override
        public PooledConnection getPooledConnection() throws SQLException {
            return getConnection(maxWait);
        }
    
        @Override
        public PooledConnection getPooledConnection(String user, String password) throws SQLException {
            throw new UnsupportedOperationException("Not supported by DruidDataSource");
        }
    
        public DruidPooledConnection getConnectionDirect(long maxWaitMillis) throws SQLException {
            int notFullTimeoutRetryCnt = 0;
            for (;;) {
                // handle notFullTimeoutRetry
                DruidPooledConnection poolableConnection;
                try {
                    poolableConnection = getConnectionInternal(maxWaitMillis);
                } catch (GetConnectionTimeoutException ex) {
                    if (notFullTimeoutRetryCnt <= this.notFullTimeoutRetryCount && !isFull()) {
                        notFullTimeoutRetryCnt++;
                        if (LOG.isWarnEnabled()) {
                            LOG.warn("get connection timeout retry : " + notFullTimeoutRetryCnt);
                        }
                        continue;
                    }
                    throw ex;
                }
    
                if (testOnBorrow) {
                    boolean validate = testConnectionInternal(poolableConnection.holder, poolableConnection.conn);
                    if (!validate) {
                        if (LOG.isDebugEnabled()) {
                            LOG.debug("skip not validate connection.");
                        }
    
                        Connection realConnection = poolableConnection.conn;
                        discardConnection(realConnection);
                        continue;
                    }
                } else {
                    Connection realConnection = poolableConnection.conn;
                    if (poolableConnection.conn.isClosed()) {
                        discardConnection(null); // 传入null，避免重复关闭
                        continue;
                    }
    
                    if (testWhileIdle) {
                        final DruidConnectionHolder holder = poolableConnection.holder;
                        long currentTimeMillis             = System.currentTimeMillis();
                        long lastActiveTimeMillis          = holder.lastActiveTimeMillis;
                        long lastKeepTimeMillis            = holder.lastKeepTimeMillis;
    
                        if (lastKeepTimeMillis > lastActiveTimeMillis) {
                            lastActiveTimeMillis = lastKeepTimeMillis;
                        }
    
                        long idleMillis                    = currentTimeMillis - lastActiveTimeMillis;
    
                        long timeBetweenEvictionRunsMillis = this.timeBetweenEvictionRunsMillis;
    
                        if (timeBetweenEvictionRunsMillis <= 0) {
                            timeBetweenEvictionRunsMillis = DEFAULT_TIME_BETWEEN_EVICTION_RUNS_MILLIS;
                        }
    
                        if (idleMillis >= timeBetweenEvictionRunsMillis
                                || idleMillis < 0 // unexcepted branch
                                ) {
                            boolean validate = testConnectionInternal(poolableConnection.holder, poolableConnection.conn);
                            if (!validate) {
                                if (LOG.isDebugEnabled()) {
                                    LOG.debug("skip not validate connection.");
                                }
    
                                discardConnection(realConnection);
                                 continue;
                            }
                        }
                    }
                }
    
                if (removeAbandoned) {
                    StackTraceElement[] stackTrace = Thread.currentThread().getStackTrace();
                    poolableConnection.connectStackTrace = stackTrace;
                    poolableConnection.setConnectedTimeNano();
                    poolableConnection.traceEnable = true;
    
                    activeConnectionLock.lock();
                    try {
                        activeConnections.put(poolableConnection, PRESENT);
                    } finally {
                        activeConnectionLock.unlock();
                    }
                }
    
                if (!this.defaultAutoCommit) {
                    poolableConnection.setAutoCommit(false);
                }
    
                return poolableConnection;
            }
        }
    
        /**
         * 抛弃连接，不进行回收，而是抛弃
         * 
         * @param realConnection
         */
        public void discardConnection(Connection realConnection) {
            JdbcUtils.close(realConnection);
    
            lock.lock();
            try {
                activeCount--;
                discardCount++;
    
                if (activeCount <= minIdle) {
                    emptySignal();
                }
            } finally {
                lock.unlock();
            }
        }
    
        private DruidPooledConnection getConnectionInternal(long maxWait) throws SQLException {
            if (closed) {
                connectErrorCountUpdater.incrementAndGet(this);
                throw new DataSourceClosedException("dataSource already closed at " + new Date(closeTimeMillis));
            }
    
            if (!enable) {
                connectErrorCountUpdater.incrementAndGet(this);
                throw new DataSourceDisableException();
            }
    
            final long nanos = TimeUnit.MILLISECONDS.toNanos(maxWait);
            final int maxWaitThreadCount = this.maxWaitThreadCount;
    
            DruidConnectionHolder holder;
    
            for (boolean createDirect = false;;) {
                if (createDirect) {
                    createStartNanosUpdater.set(this, System.nanoTime());
                    if (creatingCountUpdater.compareAndSet(this, 0, 1)) {
                        PhysicalConnectionInfo pyConnInfo = DruidDataSource.this.createPhysicalConnection();
                        holder = new DruidConnectionHolder(this, pyConnInfo);
                        holder.lastActiveTimeMillis = System.currentTimeMillis();
    
                        creatingCountUpdater.decrementAndGet(this);
                        directCreateCountUpdater.incrementAndGet(this);
    
                        if (LOG.isDebugEnabled()) {
                            LOG.debug("conn-direct_create ");
                        }
    
                        boolean discard = false;
                        lock.lock();
                        try {
                            if (activeCount < maxActive) {
                                activeCount++;
                                if (activeCount > activePeak) {
                                    activePeak = activeCount;
                                    activePeakTime = System.currentTimeMillis();
                                }
                                break;
                            } else {
                                discard = true;
                            }
                        } finally {
                            lock.unlock();
                        }
    
                        if (discard) {
                            JdbcUtils.close(pyConnInfo.getPhysicalConnection());
                        }
                    }
                }
    
                try {
                    lock.lockInterruptibly();
                } catch (InterruptedException e) {
                    connectErrorCountUpdater.incrementAndGet(this);
                    throw new SQLException("interrupt", e);
                }
    
                try {
                    if (maxWaitThreadCount > 0
                            && notEmptyWaitThreadCount >= maxWaitThreadCount) {
                        connectErrorCountUpdater.incrementAndGet(this);
                        throw new SQLException("maxWaitThreadCount " + maxWaitThreadCount + ", current wait Thread count "
                                + lock.getQueueLength());
                    }
    
                    if (onFatalError
                            && onFatalErrorMaxActive > 0
                            && activeCount >= onFatalErrorMaxActive) {
                        connectErrorCountUpdater.incrementAndGet(this);
    
                        StringBuilder errorMsg = new StringBuilder();
                        errorMsg.append("onFatalError, activeCount ")
                                .append(activeCount)
                                .append(", onFatalErrorMaxActive ")
                                .append(onFatalErrorMaxActive);
    
                        if (lastFatalErrorTimeMillis > 0) {
                            errorMsg.append(", time '")
                                    .append(StringUtils.formatDateTime19(
                                            lastFatalErrorTimeMillis, TimeZone.getDefault()))
                                    .append("'");
                        }
    
                        if (lastFatalErrorSql != null) {
                            errorMsg.append(", sql \n")
                                    .append(lastFatalErrorSql);
                        }
    
                        throw new SQLException(
                                errorMsg.toString(), lastFatalError);
                    }
    
                    connectCount++;
    
                    if (createScheduler != null
                            && poolingCount == 0
                            && activeCount < maxActive
                            && creatingCountUpdater.get(this) == 0
                            && createScheduler instanceof ScheduledThreadPoolExecutor) {
                        ScheduledThreadPoolExecutor executor = (ScheduledThreadPoolExecutor) createScheduler;
                        if (executor.getQueue().size() > 0) {
                            createDirect = true;
                            continue;
                        }
                    }
    
                    if (maxWait > 0) {
                        holder = pollLast(nanos);
                    } else {
                        holder = takeLast();
                    }
    
                    if (holder != null) {
                        activeCount++;
                        if (activeCount > activePeak) {
                            activePeak = activeCount;
                            activePeakTime = System.currentTimeMillis();
                        }
                    }
                } catch (InterruptedException e) {
                    connectErrorCountUpdater.incrementAndGet(this);
                    throw new SQLException(e.getMessage(), e);
                } catch (SQLException e) {
                    connectErrorCountUpdater.incrementAndGet(this);
                    throw e;
                } finally {
                    lock.unlock();
                }
    
                break;
            }
    
            if (holder == null) {
                long waitNanos = waitNanosLocal.get();
    
                StringBuilder buf = new StringBuilder(128);
                buf.append("wait millis ")//
                   .append(waitNanos / (1000 * 1000))//
                   .append(", active ").append(activeCount)//
                   .append(", maxActive ").append(maxActive)//
                   .append(", creating ").append(creatingCount)//
                ;
                if (creatingCount > 0 && createStartNanos > 0) {
                    long createElapseMillis = (System.nanoTime() - createStartNanos) / (1000 * 1000);
                    if (createElapseMillis > 0) {
                        buf.append(", createElapseMillis ").append(createElapseMillis);
                    }
                }
    
                if (createErrorCount > 0) {
                    buf.append(", createErrorCount ").append(createErrorCount);
                }
    
                List<JdbcSqlStatValue> sqlList = this.getDataSourceStat().getRuningSqlList();
                for (int i = 0; i < sqlList.size(); ++i) {
                    if (i != 0) {
                        buf.append('\n');
                    } else {
                        buf.append(", ");
                    }
                    JdbcSqlStatValue sql = sqlList.get(i);
                    buf.append("runningSqlCount ").append(sql.getRunningCount());
                    buf.append(" : ");
                    buf.append(sql.getSql());
                }
    
                String errorMessage = buf.toString();
    
                if (this.createError != null) {
                    throw new GetConnectionTimeoutException(errorMessage, createError);
                } else {
                    throw new GetConnectionTimeoutException(errorMessage);
                }
            }
    
            holder.incrementUseCount();
    
            DruidPooledConnection poolalbeConnection = new DruidPooledConnection(holder);
            return poolalbeConnection;
        }
    
        public void handleConnectionException(DruidPooledConnection pooledConnection, Throwable t, String sql) throws SQLException {
            final DruidConnectionHolder holder = pooledConnection.getConnectionHolder();
    
            errorCountUpdater.incrementAndGet(this);
            lastError = t;
            lastErrorTimeMillis = System.currentTimeMillis();
    
            if (t instanceof SQLException) {
                SQLException sqlEx = (SQLException) t;
    
                // broadcastConnectionError
                ConnectionEvent event = new ConnectionEvent(pooledConnection, sqlEx);
                for (ConnectionEventListener eventListener : holder.getConnectionEventListeners()) {
                    eventListener.connectionErrorOccurred(event);
                }
    
                // exceptionSorter.isExceptionFatal
                if (exceptionSorter != null && exceptionSorter.isExceptionFatal(sqlEx)) {
                    handleFatalError(pooledConnection, sqlEx, sql);
                }
    
                throw sqlEx;
            } else {
                throw new SQLException("Error", t);
            }
        }
    
        protected final void handleFatalError(DruidPooledConnection conn, SQLException error, String sql) throws SQLException {
            final DruidConnectionHolder holder = conn.holder;
    
            if (conn.isTraceEnable()) {
                activeConnectionLock.lock();
                try {
                    if (conn.isTraceEnable()) {
                        activeConnections.remove(conn);
                        conn.setTraceEnable(false);
                    }
                } finally {
                    activeConnectionLock.unlock();
                }
            }
    
            long lastErrorTimeMillis = this.lastErrorTimeMillis;
            if (lastErrorTimeMillis == 0) {
                lastErrorTimeMillis = System.currentTimeMillis();
            }
    
            if (sql != null && sql.length() > 1024) {
                sql = sql.substring(0, 1024);
            }
    
            boolean requireDiscard = false;
            final ReentrantLock lock = conn.lock;
            lock.lock();
            try {
                if ((!conn.isClosed()) || !conn.isDisable()) {
                    holder.setDiscard(true);
                    conn.disable(error);
                    requireDiscard = true;
                }
    
                lastFatalErrorTimeMillis = lastErrorTimeMillis;
                onFatalError = true;
                lastFatalError = error;
                lastFatalErrorSql = sql;
            } finally {
                lock.unlock();
            }
    
            if (requireDiscard) {
                if (holder.statementTrace != null) {
                    holder.lock.lock();
                    try {
                        for (Statement stmt : holder.statementTrace) {
                            JdbcUtils.close(stmt);
                        }
                    } finally {
                        holder.lock.unlock();
                    }
                }
    
                this.discardConnection(holder.getConnection());
                holder.setDiscard(true);
            }
    
            LOG.error("discard connection", error);
        }
    
        /**
         * 回收连接
         */
        protected void recycle(DruidPooledConnection pooledConnection) throws SQLException {
            final DruidConnectionHolder holder = pooledConnection.holder;
    
            if (holder == null) {
                LOG.warn("connectionHolder is null");
                return;
            }
    
            if (logDifferentThread //
                && (!isAsyncCloseConnectionEnable()) //
                && pooledConnection.ownerThread != Thread.currentThread()//
            ) {
                LOG.warn("get/close not same thread");
            }
    
            final Connection physicalConnection = holder.conn;
    
            if (pooledConnection.traceEnable) {
                Object oldInfo = null;
                activeConnectionLock.lock();
                try {
                    if (pooledConnection.traceEnable) {
                        oldInfo = activeConnections.remove(pooledConnection);
                        pooledConnection.traceEnable = false;
                    }
                } finally {
                    activeConnectionLock.unlock();
                }
                if (oldInfo == null) {
                    if (LOG.isWarnEnabled()) {
                        LOG.warn("remove abandonded failed. activeConnections.size " + activeConnections.size());
                    }
                }
            }
    
            final boolean isAutoCommit = holder.underlyingAutoCommit;
            final boolean isReadOnly = holder.underlyingReadOnly;
            final boolean testOnReturn = this.testOnReturn;
    
            try {
                // check need to rollback?
                if ((!isAutoCommit) && (!isReadOnly)) {
                    pooledConnection.rollback();
                }
    
                // reset holder, restore default settings, clear warnings
                boolean isSameThread = pooledConnection.ownerThread == Thread.currentThread();
                if (!isSameThread) {
                    final ReentrantLock lock = pooledConnection.lock;
                    lock.lock();
                    try {
                        holder.reset();
                    } finally {
                        lock.unlock();
                    }
                } else {
                    holder.reset();
                }
    
                if (holder.discard) {
                    return;
                }
    
                if (phyMaxUseCount > 0 && holder.useCount >= phyMaxUseCount) {
                    discardConnection(holder.conn);
                    return;
                }
    
                if (physicalConnection.isClosed()) {
                    lock.lock();
                    try {
                        activeCount--;
                        closeCount++;
                    } finally {
                        lock.unlock();
                    }
                    return;
                }
    
                if (testOnReturn) {
                    boolean validate = testConnectionInternal(holder, physicalConnection);
                    if (!validate) {
                        JdbcUtils.close(physicalConnection);
    
                        destroyCountUpdater.incrementAndGet(this);
    
                        lock.lock();
                        try {
                            activeCount--;
                            closeCount++;
                        } finally {
                            lock.unlock();
                        }
                        return;
                    }
                }
    
                if (!enable) {
                    discardConnection(holder.conn);
                    return;
                }
    
                boolean result;
                final long currentTimeMillis = System.currentTimeMillis();
    
                if (phyTimeoutMillis > 0) {
                    long phyConnectTimeMillis = currentTimeMillis - holder.connectTimeMillis;
                    if (phyConnectTimeMillis > phyTimeoutMillis) {
                        discardConnection(holder.conn);
                        return;
                    }
                }
    
                lock.lock();
                try {
                    activeCount--;
                    closeCount++;
    
                    result = putLast(holder, currentTimeMillis);
                    recycleCount++;
                } finally {
                    lock.unlock();
                }
    
                if (!result) {
                    JdbcUtils.close(holder.conn);
                    LOG.info("connection recyle failed.");
                }
            } catch (Throwable e) {
                holder.clearStatementCache();
    
                if (!holder.discard) {
                    this.discardConnection(physicalConnection);
                    holder.discard = true;
                }
    
                LOG.error("recyle error", e);
                recycleErrorCountUpdater.incrementAndGet(this);
            }
        }
    
        public long getRecycleErrorCount() {
            return recycleErrorCount;
        }
    
        public void clearStatementCache() throws SQLException {
            lock.lock();
            try {
                for (int i = 0; i < poolingCount; ++i) {
                    DruidConnectionHolder conn = connections[i];
    
                    if (conn.statementPool != null) {
                        conn.statementPool.clear();
                    }
                }
            } finally {
                lock.unlock();
            }
        }
    
        /**
         * close datasource
         */
        public void close() {
            if (LOG.isInfoEnabled()) {
                LOG.info("{dataSource-" + this.getID() + "} closing ...");
            }
    
            lock.lock();
            try {
                if (this.closed) {
                    return;
                }
    
                if (!this.inited) {
                    return;
                }
    
                this.closing = true;
    
                if (logStatsThread != null) {
                    logStatsThread.interrupt();
                }
    
                if (createConnectionThread != null) {
                    createConnectionThread.interrupt();
                }
    
                if (destroyConnectionThread != null) {
                    destroyConnectionThread.interrupt();
                }
    
                if (createSchedulerFuture != null) {
                    createSchedulerFuture.cancel(true);
                }
    
                if (destroySchedulerFuture != null) {
                    destroySchedulerFuture.cancel(true);
                }
    
                for (int i = 0; i < poolingCount; ++i) {
                    DruidConnectionHolder connHolder = connections[i];
    
                    for (PreparedStatementHolder stmtHolder : connHolder.getStatementPool().getMap().values()) {
                        connHolder.getStatementPool().closeRemovedStatement(stmtHolder);
                    }
                    connHolder.getStatementPool().getMap().clear();
    
                    Connection physicalConnection = connHolder.getConnection();
                    try {
                        physicalConnection.close();
                    } catch (Exception ex) {
                        LOG.warn("close connection error", ex);
                    }
                    connections[i] = null;
                    destroyCountUpdater.incrementAndGet(this);
                }
                poolingCount = 0;
                unregisterMbean();
    
                enable = false;
                notEmpty.signalAll();
                notEmptySignalCount++;
    
                this.closed = true;
                this.closeTimeMillis = System.currentTimeMillis();
    
                for (Filter filter : filters) {
                    filter.destroy();
                }
            } finally {
                lock.unlock();
            }
    
            if (LOG.isInfoEnabled()) {
                LOG.info("{dataSource-" + this.getID() + "} closed");
            }
        }
    
        public void registerMbean() {
            if (!mbeanRegistered) {
                AccessController.doPrivileged(new PrivilegedAction<Object>() {
    
                    @Override
                    public Object run() {
                        ObjectName objectName = DruidDataSourceStatManager.addDataSource(DruidDataSource.this,
                                                                                         DruidDataSource.this.name);
    
                        DruidDataSource.this.setObjectName(objectName);
                        DruidDataSource.this.mbeanRegistered = true;
    
                        return null;
                    }
                });
            }
        }
    
        public void unregisterMbean() {
            if (mbeanRegistered) {
                AccessController.doPrivileged(new PrivilegedAction<Object>() {
    
                    @Override
                    public Object run() {
                        DruidDataSourceStatManager.removeDataSource(DruidDataSource.this);
                        DruidDataSource.this.mbeanRegistered = false;
                        return null;
                    }
                });
            }
        }
    
        public boolean isMbeanRegistered() {
            return mbeanRegistered;
        }
    
        boolean putLast(DruidConnectionHolder e, long lastActiveTimeMillis) {
            if (poolingCount >= maxActive) {
                return false;
            }
    
            e.lastActiveTimeMillis = lastActiveTimeMillis;
            connections[poolingCount] = e;
            incrementPoolingCount();
    
            if (poolingCount > poolingPeak) {
                poolingPeak = poolingCount;
                poolingPeakTime = lastActiveTimeMillis;
            }
    
            notEmpty.signal();
            notEmptySignalCount++;
    
            return true;
        }
    
        DruidConnectionHolder takeLast() throws InterruptedException, SQLException {
            try {
                while (poolingCount == 0) {
                    emptySignal(); // send signal to CreateThread create connection
    
                    if (failFast && isFailContinuous()) {
                        throw new DataSourceNotAvailableException(createError);
                    }
    
                    notEmptyWaitThreadCount++;
                    if (notEmptyWaitThreadCount > notEmptyWaitThreadPeak) {
                        notEmptyWaitThreadPeak = notEmptyWaitThreadCount;
                    }
                    try {
                        notEmpty.await(); // signal by recycle or creator
                    } finally {
                        notEmptyWaitThreadCount--;
                    }
                    notEmptyWaitCount++;
    
                    if (!enable) {
                        connectErrorCountUpdater.incrementAndGet(this);
                        throw new DataSourceDisableException();
                    }
                }
            } catch (InterruptedException ie) {
                notEmpty.signal(); // propagate to non-interrupted thread
                notEmptySignalCount++;
                throw ie;
            }
    
            decrementPoolingCount();
            DruidConnectionHolder last = connections[poolingCount];
            connections[poolingCount] = null;
    
            return last;
        }
    
        private DruidConnectionHolder pollLast(long nanos) throws InterruptedException, SQLException {
            long estimate = nanos;
    
            for (;;) {
                if (poolingCount == 0) {
                    emptySignal(); // send signal to CreateThread create connection
    
                    if (failFast && isFailContinuous()) {
                        throw new DataSourceNotAvailableException(createError);
                    }
    
                    if (estimate <= 0) {
                        waitNanosLocal.set(nanos - estimate);
                        return null;
                    }
    
                    notEmptyWaitThreadCount++;
                    if (notEmptyWaitThreadCount > notEmptyWaitThreadPeak) {
                        notEmptyWaitThreadPeak = notEmptyWaitThreadCount;
                    }
    
                    try {
                        long startEstimate = estimate;
                        estimate = notEmpty.awaitNanos(estimate); // signal by
                                                                  // recycle or
                                                                  // creator
                        notEmptyWaitCount++;
                        notEmptyWaitNanos += (startEstimate - estimate);
    
                        if (!enable) {
                            connectErrorCountUpdater.incrementAndGet(this);
                            throw new DataSourceDisableException();
                        }
                    } catch (InterruptedException ie) {
                        notEmpty.signal(); // propagate to non-interrupted thread
                        notEmptySignalCount++;
                        throw ie;
                    } finally {
                        notEmptyWaitThreadCount--;
                    }
    
                    if (poolingCount == 0) {
                        if (estimate > 0) {
                            continue;
                        }
    
                        waitNanosLocal.set(nanos - estimate);
                        return null;
                    }
                }
    
                decrementPoolingCount();
                DruidConnectionHolder last = connections[poolingCount];
                connections[poolingCount] = null;
    
                long waitNanos = nanos - estimate;
                last.setLastNotEmptyWaitNanos(waitNanos);
    
                return last;
            }
        }
    
        private final void decrementPoolingCount() {
            poolingCount--;
        }
    
        private final void incrementPoolingCount() {
            poolingCount++;
        }
    
        @Override
        public Connection getConnection(String username, String password) throws SQLException {
            if (this.username == null
                    && this.password == null
                    && username != null
                    && password != null) {
                this.username = username;
                this.password = password;
    
                return getConnection();
            }
    
            if (!StringUtils.equals(username, this.username)) {
                throw new UnsupportedOperationException("Not supported by DruidDataSource");
            }
    
            if (!StringUtils.equals(password, this.password)) {
                throw new UnsupportedOperationException("Not supported by DruidDataSource");
            }
    
            return getConnection();
        }
    
        public long getCreateCount() {
            return createCount;
        }
    
        public long getDestroyCount() {
            return destroyCount;
        }
    
        public long getConnectCount() {
            lock.lock();
            try {
                return connectCount;
            } finally {
                lock.unlock();
            }
        }
    
        public long getCloseCount() {
            return closeCount;
        }
    
        public long getConnectErrorCount() {
            return connectErrorCountUpdater.get(this);
        }
    
        @Override
        public int getPoolingCount() {
            lock.lock();
            try {
                return poolingCount;
            } finally {
                lock.unlock();
            }
        }
    
        public int getPoolingPeak() {
            lock.lock();
            try {
                return poolingPeak;
            } finally {
                lock.unlock();
            }
        }
    
        public Date getPoolingPeakTime() {
            if (poolingPeakTime <= 0) {
                return null;
            }
    
            return new Date(poolingPeakTime);
        }
    
        public long getRecycleCount() {
            return recycleCount;
        }
    
        public int getActiveCount() {
            lock.lock();
            try {
                return activeCount;
            } finally {
                lock.unlock();
            }
        }
    
        public void logStats() {
            final DruidDataSourceStatLogger statLogger = this.statLogger;
            if (statLogger == null) {
                return;
            }
    
            DruidDataSourceStatValue statValue = getStatValueAndReset();
    
            statLogger.log(statValue);
        }
    
        public DruidDataSourceStatValue getStatValueAndReset() {
            DruidDataSourceStatValue value = new DruidDataSourceStatValue();
    
            lock.lock();
            try {
                value.setPoolingCount(this.poolingCount);
                value.setPoolingPeak(this.poolingPeak);
                value.setPoolingPeakTime(this.poolingPeakTime);
    
                value.setActiveCount(this.activeCount);
                value.setActivePeak(this.activePeak);
                value.setActivePeakTime(this.activePeakTime);
    
                value.setConnectCount(this.connectCount);
                value.setCloseCount(this.closeCount);
                value.setWaitThreadCount(lock.getWaitQueueLength(notEmpty));
                value.setNotEmptyWaitCount(this.notEmptyWaitCount);
                value.setNotEmptyWaitNanos(this.notEmptyWaitNanos);
                value.setKeepAliveCheckCount(this.keepAliveCheckCount);
    
                // reset
                this.poolingPeak = 0;
                this.poolingPeakTime = 0;
                this.activePeak = 0;
                this.activePeakTime = 0;
                this.connectCount = 0;
                this.closeCount = 0;
                this.keepAliveCheckCount = 0;
    
                this.notEmptyWaitCount = 0;
                this.notEmptyWaitNanos = 0;
            } finally {
                lock.unlock();
            }
    
            value.setName(this.getName());
            value.setDbType(this.dbType);
            value.setDriverClassName(this.getDriverClassName());
    
            value.setUrl(this.getUrl());
            value.setUserName(this.getUsername());
            value.setFilterClassNames(this.getFilterClassNames());
    
            value.setInitialSize(this.getInitialSize());
            value.setMinIdle(this.getMinIdle());
            value.setMaxActive(this.getMaxActive());
    
            value.setQueryTimeout(this.getQueryTimeout());
            value.setTransactionQueryTimeout(this.getTransactionQueryTimeout());
            value.setLoginTimeout(this.getLoginTimeout());
            value.setValidConnectionCheckerClassName(this.getValidConnectionCheckerClassName());
            value.setExceptionSorterClassName(this.getExceptionSorterClassName());
    
            value.setTestOnBorrow(this.testOnBorrow);
            value.setTestOnReturn(this.testOnReturn);
            value.setTestWhileIdle(this.testWhileIdle);
    
            value.setDefaultAutoCommit(this.isDefaultAutoCommit());
    
            if (defaultReadOnly != null) {
                value.setDefaultReadOnly(defaultReadOnly);
            }
            value.setDefaultTransactionIsolation(this.getDefaultTransactionIsolation());
    
            value.setLogicConnectErrorCount(connectErrorCountUpdater.getAndSet(this, 0));
    
            value.setPhysicalConnectCount(createCountUpdater.getAndSet(this, 0));
            value.setPhysicalCloseCount(destroyCountUpdater.getAndSet(this, 0));
            value.setPhysicalConnectErrorCount(createErrorCountUpdater.getAndSet(this, 0));
    
            value.setExecuteCount(this.getAndResetExecuteCount());
            value.setErrorCount(errorCountUpdater.getAndSet(this, 0));
            value.setCommitCount(commitCountUpdater.getAndSet(this, 0));
            value.setRollbackCount(rollbackCountUpdater.getAndSet(this, 0));
    
            value.setPstmtCacheHitCount(cachedPreparedStatementHitCountUpdater.getAndSet(this,0));
            value.setPstmtCacheMissCount(cachedPreparedStatementMissCountUpdater.getAndSet(this, 0));
    
            value.setStartTransactionCount(startTransactionCountUpdater.getAndSet(this, 0));
            value.setTransactionHistogram(this.getTransactionHistogram().toArrayAndReset());
    
            value.setConnectionHoldTimeHistogram(this.getDataSourceStat().getConnectionHoldHistogram().toArrayAndReset());
            value.setRemoveAbandoned(this.isRemoveAbandoned());
            value.setClobOpenCount(this.getDataSourceStat().getClobOpenCountAndReset());
            value.setBlobOpenCount(this.getDataSourceStat().getBlobOpenCountAndReset());
    
            value.setSqlSkipCount(this.getDataSourceStat().getSkipSqlCountAndReset());
            value.setSqlList(this.getDataSourceStat().getSqlStatMapAndReset());
    
            return value;
        }
    
        public long getRemoveAbandonedCount() {
            return removeAbandonedCount;
        }
    
        protected boolean put(PhysicalConnectionInfo physicalConnectionInfo) {
            DruidConnectionHolder holder = null;
            try {
                holder = new DruidConnectionHolder(DruidDataSource.this, physicalConnectionInfo);
            } catch (SQLException ex) {
                lock.lock();
                try {
                    if (createScheduler != null) {
                        createTaskCount--;
                    }
                } finally {
                    lock.unlock();
                }
                LOG.error("create connection holder error", ex);
                return false;
            }
    
            return put(holder);
        }
    
        private boolean put(DruidConnectionHolder holder) {
            lock.lock();
            try {
                if (poolingCount >= maxActive) {
                    return false;
                }
                connections[poolingCount] = holder;
                incrementPoolingCount();
    
                if (poolingCount > poolingPeak) {
                    poolingPeak = poolingCount;
                    poolingPeakTime = System.currentTimeMillis();
                }
    
                notEmpty.signal();
                notEmptySignalCount++;
    
                if (createScheduler != null) {
                    createTaskCount--;
    
                    if (poolingCount + createTaskCount < notEmptyWaitThreadCount //
                        && activeCount + poolingCount + createTaskCount < maxActive) {
                        emptySignal();
                    }
                }
            } finally {
                lock.unlock();
            }
            return true;
        }
    
        public class CreateConnectionTask implements Runnable {
    
            private int errorCount   = 0;
            private boolean initTask = false;
    
            public CreateConnectionTask() {
    
            }
    
            public CreateConnectionTask(boolean initTask) {
                this.initTask = initTask;
            }
    
            @Override
            public void run() {
                runInternal();
            }
    
            private void runInternal() {
                for (;;) {
    
                    // addLast
                    lock.lock();
                    try {
                        if (closed || closing) {
                            createTaskCount--;
                            return;
                        }
    
                        boolean emptyWait = true;
    
                        if (createError != null && poolingCount == 0) {
                            emptyWait = false;
                        }
    
                        if (emptyWait) {
                            // 必须存在线程等待，才创建连接
                            if (poolingCount >= notEmptyWaitThreadCount //
                                    && (!(keepAlive && activeCount + poolingCount < minIdle))
                                    && (!initTask)
                                    && !isFailContinuous()
                            ) {
                                createTaskCount--;
                                return;
                            }
    
                            // 防止创建超过maxActive数量的连接
                            if (activeCount + poolingCount >= maxActive) {
                                createTaskCount--;
                                return;
                            }
                        }
                    } finally {
                        lock.unlock();
                    }
    
                    PhysicalConnectionInfo physicalConnection = null;
    
                    try {
                        physicalConnection = createPhysicalConnection();
                    } catch (OutOfMemoryError e) {
                        LOG.error("create connection OutOfMemoryError, out memory. ", e);
    
                        errorCount++;
                        if (errorCount > connectionErrorRetryAttempts && timeBetweenConnectErrorMillis > 0) {
                            // fail over retry attempts
                            setFailContinuous(true);
                            if (failFast) {
                                lock.lock();
                                try {
                                    notEmpty.signalAll();
                                } finally {
                                    lock.unlock();
                                }
                            }
    
                            if (breakAfterAcquireFailure) {
                                lock.lock();
                                try {
                                    createTaskCount--;
                                } finally {
                                    lock.unlock();
                                }
                                return;
                            }
    
                            this.errorCount = 0; // reset errorCount
                            if (closing || closed) {
                                createTaskCount--;
                                return;
                            }
                            createSchedulerFuture = createScheduler.schedule(this, timeBetweenConnectErrorMillis, TimeUnit.MILLISECONDS);
                            return;
                        }
                    } catch (SQLException e) {
                        LOG.error("create connection SQLException, url: " + jdbcUrl, e);
    
                        errorCount++;
                        if (errorCount > connectionErrorRetryAttempts && timeBetweenConnectErrorMillis > 0) {
                            // fail over retry attempts
                            setFailContinuous(true);
                            if (failFast) {
                                lock.lock();
                                try {
                                    notEmpty.signalAll();
                                } finally {
                                    lock.unlock();
                                }
                            }
    
                            if (breakAfterAcquireFailure) {
                                lock.lock();
                                try {
                                    createTaskCount--;
                                } finally {
                                    lock.unlock();
                                }
                                return;
                            }
    
                            this.errorCount = 0; // reset errorCount
                            if (closing || closed) {
                                createTaskCount--;
                                return;
                            }
                            createSchedulerFuture = createScheduler.schedule(this, timeBetweenConnectErrorMillis, TimeUnit.MILLISECONDS);
                            return;
                        }
                    } catch (RuntimeException e) {
                        LOG.error("create connection RuntimeException", e);
                        // unknow fatal exception
                        setFailContinuous(true);
                        continue;
                    } catch (Error e) {
                        lock.lock();
                        try {
                            createTaskCount--;
                        } finally {
                            lock.unlock();
                        }
                        LOG.error("create connection Error", e);
                        // unknow fatal exception
                        setFailContinuous(true);
                        break;
                    } catch (Throwable e) {
                        LOG.error("create connection unexecpted error.", e);
                        break;
                    }
    
                    if (physicalConnection == null) {
                        continue;
                    }
    
                    boolean result = put(physicalConnection);
                    if (!result) {
                        JdbcUtils.close(physicalConnection.getPhysicalConnection());
                        LOG.info("put physical connection to pool failed.");
                    }
                    break;
                }
            }
        }
    
        public class CreateConnectionThread extends Thread {
    
            public CreateConnectionThread(String name){
                super(name);
                this.setDaemon(true);
            }
    
            public void run() {
                initedLatch.countDown();
    
                long lastDiscardCount = 0;
                int errorCount = 0;
                for (;;) {
                    // addLast
                    try {
                        lock.lockInterruptibly();
                    } catch (InterruptedException e2) {
                        break;
                    }
    
                    long discardCount = DruidDataSource.this.discardCount;
                    boolean discardChanged = discardCount - lastDiscardCount > 0;
                    lastDiscardCount = discardCount;
    
                    try {
                        boolean emptyWait = true;
    
                        if (createError != null
                                && poolingCount == 0
                                && !discardChanged) {
                            emptyWait = false;
                        }
    
                        if (emptyWait
                                && asyncInit && createCount < initialSize) {
                            emptyWait = false;
                        }
    
                        if (emptyWait) {
                            // 必须存在线程等待，才创建连接
                            if (poolingCount >= notEmptyWaitThreadCount //
                                    && (!(keepAlive && activeCount + poolingCount < minIdle))
                                    && !isFailContinuous()
                            ) {
                                empty.await();
                            }
    
                            // 防止创建超过maxActive数量的连接
                            if (activeCount + poolingCount >= maxActive) {
                                empty.await();
                                continue;
                            }
                        }
    
                    } catch (InterruptedException e) {
                        lastCreateError = e;
                        lastErrorTimeMillis = System.currentTimeMillis();
    
                        if (!closing) {
                            LOG.error("create connection Thread Interrupted, url: " + jdbcUrl, e);
                        }
                        break;
                    } finally {
                        lock.unlock();
                    }
    
                    PhysicalConnectionInfo connection = null;
    
                    try {
                        connection = createPhysicalConnection();
                    } catch (SQLException e) {
                        LOG.error("create connection SQLException, url: " + jdbcUrl + ", errorCode " + e.getErrorCode()
                                  + ", state " + e.getSQLState(), e);
    
                        errorCount++;
                        if (errorCount > connectionErrorRetryAttempts && timeBetweenConnectErrorMillis > 0) {
                            // fail over retry attempts
                            setFailContinuous(true);
                            if (failFast) {
                                lock.lock();
                                try {
                                    notEmpty.signalAll();
                                } finally {
                                    lock.unlock();
                                }
                            }
    
                            if (breakAfterAcquireFailure) {
                                break;
                            }
    
                            try {
                                Thread.sleep(timeBetweenConnectErrorMillis);
                            } catch (InterruptedException interruptEx) {
                                break;
                            }
                        }
                    } catch (RuntimeException e) {
                        LOG.error("create connection RuntimeException", e);
                        setFailContinuous(true);
                        continue;
                    } catch (Error e) {
                        LOG.error("create connection Error", e);
                        setFailContinuous(true);
                        break;
                    }
    
                    if (connection == null) {
                        continue;
                    }
    
                    boolean result = put(connection);
                    if (!result) {
                        JdbcUtils.close(connection.getPhysicalConnection());
                        LOG.info("put physical connection to pool failed.");
                    }
    
                    errorCount = 0; // reset errorCount
                }
            }
        }
    
        public class DestroyConnectionThread extends Thread {
    
            public DestroyConnectionThread(String name){
                super(name);
                this.setDaemon(true);
            }
    
            public void run() {
                initedLatch.countDown();
    
                for (;;) {
                    // 从前面开始删除
                    try {
                        if (closed) {
                            break;
                        }
    
                        if (timeBetweenEvictionRunsMillis > 0) {
                            Thread.sleep(timeBetweenEvictionRunsMillis);
                        } else {
                            Thread.sleep(1000); //
                        }
    
                        if (Thread.interrupted()) {
                            break;
                        }
    
                        destroyTask.run();
                    } catch (InterruptedException e) {
                        break;
                    }
                }
            }
    
        }
    
        public class DestroyTask implements Runnable {
            public DestroyTask() {
    
            }
    
            @Override
            public void run() {
                shrink(true, keepAlive);
    
                if (isRemoveAbandoned()) {
                    removeAbandoned();
                }
            }
    
        }
    
        public class LogStatsThread extends Thread {
    
            public LogStatsThread(String name){
                super(name);
                this.setDaemon(true);
            }
    
            public void run() {
                try {
                    for (;;) {
                        try {
                            logStats();
                        } catch (Exception e) {
                            LOG.error("logStats error", e);
                        }
    
                        Thread.sleep(timeBetweenLogStatsMillis);
                    }
                } catch (InterruptedException e) {
                    // skip
                }
            }
        }
    
        public int removeAbandoned() {
            int removeCount = 0;
    
            long currrentNanos = System.nanoTime();
    
            List<DruidPooledConnection> abandonedList = new ArrayList<DruidPooledConnection>();
    
            activeConnectionLock.lock();
            try {
                Iterator<DruidPooledConnection> iter = activeConnections.keySet().iterator();
    
                for (; iter.hasNext();) {
                    DruidPooledConnection pooledConnection = iter.next();
    
                    if (pooledConnection.isRunning()) {
                        continue;
                    }
    
                    long timeMillis = (currrentNanos - pooledConnection.getConnectedTimeNano()) / (1000 * 1000);
    
                    if (timeMillis >= removeAbandonedTimeoutMillis) {
                        iter.remove();
                        pooledConnection.setTraceEnable(false);
                        abandonedList.add(pooledConnection);
                    }
                }
            } finally {
                activeConnectionLock.unlock();
            }
    
            if (abandonedList.size() > 0) {
                for (DruidPooledConnection pooledConnection : abandonedList) {
                    final ReentrantLock lock = pooledConnection.lock;
                    lock.lock();
                    try {
                        if (pooledConnection.isDisable()) {
                            continue;
                        }
                    } finally {
                        lock.unlock();
                    }
    
                    JdbcUtils.close(pooledConnection);
                    pooledConnection.abandond();
                    removeAbandonedCount++;
                    removeCount++;
    
                    if (isLogAbandoned()) {
                        StringBuilder buf = new StringBuilder();
                        buf.append("abandon connection, owner thread: ");
                        buf.append(pooledConnection.getOwnerThread().getName());
                        buf.append(", connected at : ");
                        buf.append(pooledConnection.getConnectedTimeMillis());
                        buf.append(", open stackTrace\n");
    
                        StackTraceElement[] trace = pooledConnection.getConnectStackTrace();
                        for (int i = 0; i < trace.length; i++) {
                            buf.append("\tat ");
                            buf.append(trace[i].toString());
                            buf.append("\n");
                        }
    
                        buf.append("ownerThread current state is " + pooledConnection.getOwnerThread().getState()
                                   + ", current stackTrace\n");
                        trace = pooledConnection.getOwnerThread().getStackTrace();
                        for (int i = 0; i < trace.length; i++) {
                            buf.append("\tat ");
                            buf.append(trace[i].toString());
                            buf.append("\n");
                        }
    
                        LOG.error(buf.toString());
                    }
                }
            }
    
            return removeCount;
        }
    
        /** Instance key */
        protected String instanceKey = null;
    
        public Reference getReference() throws NamingException {
            final String className = getClass().getName();
            final String factoryName = className + "Factory"; // XXX: not robust
            Reference ref = new Reference(className, factoryName, null);
            ref.add(new StringRefAddr("instanceKey", instanceKey));
            ref.add(new StringRefAddr("url", this.getUrl()));
            ref.add(new StringRefAddr("username", this.getUsername()));
            ref.add(new StringRefAddr("password", this.getPassword()));
            // TODO ADD OTHER PROPERTIES
            return ref;
        }
    
        @Override
        public List<String> getFilterClassNames() {
            List<String> names = new ArrayList<String>();
            for (Filter filter : filters) {
                names.add(filter.getClass().getName());
            }
            return names;
        }
    
        public int getRawDriverMajorVersion() {
            int version = -1;
            if (this.driver != null) {
                version = driver.getMajorVersion();
            }
            return version;
        }
    
        public int getRawDriverMinorVersion() {
            int version = -1;
            if (this.driver != null) {
                version = driver.getMinorVersion();
            }
            return version;
        }
    
        public String getProperties() {
            Properties properties = new Properties();
            properties.putAll(connectProperties);
            if (properties.containsKey("password")) {
                properties.put("password", "******");
            }
            return properties.toString();
        }
    
        @Override
        public void shrink() {
            shrink(false, false);
        }
    
        public void shrink(boolean checkTime) {
            shrink(checkTime, keepAlive);
        }
    
        public void shrink(boolean checkTime, boolean keepAlive) {
            try {
                lock.lockInterruptibly();
            } catch (InterruptedException e) {
                return;
            }
    
            int evictCount = 0;
            int keepAliveCount = 0;
            try {
                if (!inited) {
                    return;
                }
    
                final int checkCount = poolingCount - minIdle;
                final long currentTimeMillis = System.currentTimeMillis();
                for (int i = 0; i < poolingCount; ++i) {
                    DruidConnectionHolder connection = connections[i];
    
                    if (checkTime) {
                        if (phyTimeoutMillis > 0) {
                            long phyConnectTimeMillis = currentTimeMillis - connection.connectTimeMillis;
                            if (phyConnectTimeMillis > phyTimeoutMillis) {
                                evictConnections[evictCount++] = connection;
                                continue;
                            }
                        }
    
                        long idleMillis = currentTimeMillis - connection.lastActiveTimeMillis;
    
                        if (idleMillis < minEvictableIdleTimeMillis
                                && idleMillis < keepAliveBetweenTimeMillis
                        ) {
                            break;
                        }
    
                        if (idleMillis >= minEvictableIdleTimeMillis) {
                            if (checkTime && i < checkCount) {
                                evictConnections[evictCount++] = connection;
                                continue;
                            } else if (idleMillis > maxEvictableIdleTimeMillis) {
                                evictConnections[evictCount++] = connection;
                                continue;
                            }
                        }
    
                        if (keepAlive && idleMillis >= keepAliveBetweenTimeMillis) {
                            keepAliveConnections[keepAliveCount++] = connection;
                        }
                    } else {
                        if (i < checkCount) {
                            evictConnections[evictCount++] = connection;
                        } else {
                            break;
                        }
                    }
                }
    
                int removeCount = evictCount + keepAliveCount;
                if (removeCount > 0) {
                    System.arraycopy(connections, removeCount, connections, 0, poolingCount - removeCount);
                    Arrays.fill(connections, poolingCount - removeCount, poolingCount, null);
                    poolingCount -= removeCount;
                }
                keepAliveCheckCount += keepAliveCount;
            } finally {
                lock.unlock();
            }
    
            if (evictCount > 0) {
                for (int i = 0; i < evictCount; ++i) {
                    DruidConnectionHolder item = evictConnections[i];
                    Connection connection = item.getConnection();
                    JdbcUtils.close(connection);
                    destroyCountUpdater.incrementAndGet(this);
                }
                Arrays.fill(evictConnections, null);
            }
    
            if (keepAliveCount > 0) {
                // keep order
                for (int i = keepAliveCount - 1; i >= 0; --i) {
                    DruidConnectionHolder holer = keepAliveConnections[i];
                    Connection connection = holer.getConnection();
                    holer.incrementKeepAliveCheckCount();
    
                    boolean validate = false;
                    try {
                        this.validateConnection(connection);
                        validate = true;
                    } catch (Throwable error) {
                        if (LOG.isDebugEnabled()) {
                            LOG.debug("keepAliveErr", error);
                        }
                        // skip
                    }
    
                    boolean discard = !validate;
                    if (validate) {
                        holer.lastKeepTimeMillis = System.currentTimeMillis();
                        boolean putOk = put(holer);
                        if (!putOk) {
                            discard = true;
                        }
                    }
    
                    if (discard) {
                        try {
                            connection.close();
                        } catch (Exception e) {
                            // skip
                        }
    
                        lock.lock();
                        try {
                            discardCount++;
    
                            if (activeCount <= minIdle) {
                                emptySignal();
                            }
                        } finally {
                            lock.unlock();
                        }
                    }
                }
                this.getDataSourceStat().addKeepAliveCheckCount(keepAliveCount);
                Arrays.fill(keepAliveConnections, null);
            }
        }
    
        public int getWaitThreadCount() {
            lock.lock();
            try {
                return lock.getWaitQueueLength(notEmpty);
            } finally {
                lock.unlock();
            }
        }
    
        public long getNotEmptyWaitCount() {
            return notEmptyWaitCount;
        }
    
        public int getNotEmptyWaitThreadCount() {
            lock.lock();
            try {
                return notEmptyWaitThreadCount;
            } finally {
                lock.unlock();
            }
        }
    
        public int getNotEmptyWaitThreadPeak() {
            lock.lock();
            try {
                return notEmptyWaitThreadPeak;
            } finally {
                lock.unlock();
            }
        }
    
        public long getNotEmptySignalCount() {
            return notEmptySignalCount;
        }
    
        public long getNotEmptyWaitMillis() {
            return notEmptyWaitNanos / (1000 * 1000);
        }
    
        public long getNotEmptyWaitNanos() {
            return notEmptyWaitNanos;
        }
    
        public int getLockQueueLength() {
            return lock.getQueueLength();
        }
    
        public int getActivePeak() {
            return activePeak;
        }
    
        public Date getActivePeakTime() {
            if (activePeakTime <= 0) {
                return null;
            }
    
            return new Date(activePeakTime);
        }
    
        public String dump() {
            lock.lock();
            try {
                return this.toString();
            } finally {
                lock.unlock();
            }
        }
    
        public long getErrorCount() {
            return this.errorCount;
        }
    
        public String toString() {
            StringBuilder buf = new StringBuilder();
    
            buf.append("{");
    
            buf.append("\n\tCreateTime:\"");
            buf.append(Utils.toString(getCreatedTime()));
            buf.append("\"");
    
            buf.append(",\n\tActiveCount:");
            buf.append(getActiveCount());
    
            buf.append(",\n\tPoolingCount:");
            buf.append(getPoolingCount());
    
            buf.append(",\n\tCreateCount:");
            buf.append(getCreateCount());
    
            buf.append(",\n\tDestroyCount:");
            buf.append(getDestroyCount());
    
            buf.append(",\n\tCloseCount:");
            buf.append(getCloseCount());
    
            buf.append(",\n\tConnectCount:");
            buf.append(getConnectCount());
    
            buf.append(",\n\tConnections:[");
            for (int i = 0; i < poolingCount; ++i) {
                DruidConnectionHolder conn = connections[i];
                if (conn != null) {
                    if (i != 0) {
                        buf.append(",");
                    }
                    buf.append("\n\t\t");
                    buf.append(conn.toString());
                }
            }
            buf.append("\n\t]");
    
            buf.append("\n}");
    
            if (this.isPoolPreparedStatements()) {
                buf.append("\n\n[");
                for (int i = 0; i < poolingCount; ++i) {
                    DruidConnectionHolder conn = connections[i];
                    if (conn != null) {
                        if (i != 0) {
                            buf.append(",");
                        }
                        buf.append("\n\t{\n\tID:");
                        buf.append(System.identityHashCode(conn.getConnection()));
                        PreparedStatementPool pool = conn.getStatementPool();
    
                        buf.append(", \n\tpoolStatements:[");
    
                        int entryIndex = 0;
                        try {
                            for (Map.Entry<PreparedStatementKey, PreparedStatementHolder> entry : pool.getMap().entrySet()) {
                                if (entryIndex != 0) {
                                    buf.append(",");
                                }
                                buf.append("\n\t\t{hitCount:");
                                buf.append(entry.getValue().getHitCount());
                                buf.append(",sql:\"");
                                buf.append(entry.getKey().getSql());
                                buf.append("\"");
                                buf.append("\t}");
    
                                entryIndex++;
                            }
                        } catch (ConcurrentModificationException e) {
                            // skip ..
                        }
    
                        buf.append("\n\t\t]");
    
                        buf.append("\n\t}");
                    }
                }
                buf.append("\n]");
            }
    
            return buf.toString();
        }
    
        public List<Map<String, Object>> getPoolingConnectionInfo() {
            List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
            lock.lock();
            try {
                for (int i = 0; i < poolingCount; ++i) {
                    DruidConnectionHolder connHolder = connections[i];
                    Connection conn = connHolder.getConnection();
    
                    Map<String, Object> map = new LinkedHashMap<String, Object>();
                    map.put("id", System.identityHashCode(conn));
                    map.put("connectionId", connHolder.getConnectionId());
                    map.put("useCount", connHolder.getUseCount());
                    if (connHolder.lastActiveTimeMillis > 0) {
                        map.put("lastActiveTime", new Date(connHolder.lastActiveTimeMillis));
                    }
                    if (connHolder.lastKeepTimeMillis > 0) {
                        map.put("lastKeepTimeMillis", new Date(connHolder.lastKeepTimeMillis));
                    }
                    map.put("connectTime", new Date(connHolder.getTimeMillis()));
                    map.put("holdability", connHolder.getUnderlyingHoldability());
                    map.put("transactionIsolation", connHolder.getUnderlyingTransactionIsolation());
                    map.put("autoCommit", connHolder.underlyingAutoCommit);
                    map.put("readoOnly", connHolder.isUnderlyingReadOnly());
    
                    if (connHolder.isPoolPreparedStatements()) {
                        List<Map<String, Object>> stmtCache = new ArrayList<Map<String, Object>>();
                        PreparedStatementPool stmtPool = connHolder.getStatementPool();
                        for (PreparedStatementHolder stmtHolder : stmtPool.getMap().values()) {
                            Map<String, Object> stmtInfo = new LinkedHashMap<String, Object>();
    
                            stmtInfo.put("sql", stmtHolder.key.getSql());
                            stmtInfo.put("defaultRowPrefetch", stmtHolder.getDefaultRowPrefetch());
                            stmtInfo.put("rowPrefetch", stmtHolder.getRowPrefetch());
                            stmtInfo.put("hitCount", stmtHolder.getHitCount());
    
                            stmtCache.add(stmtInfo);
                        }
    
                        map.put("pscache", stmtCache);
                    }
                    map.put("keepAliveCheckCount", connHolder.getKeepAliveCheckCount());
    
                    list.add(map);
                }
            } finally {
                lock.unlock();
            }
            return list;
        }
    
        public void logTransaction(TransactionInfo info) {
            long transactionMillis = info.getEndTimeMillis() - info.getStartTimeMillis();
            if (transactionThresholdMillis > 0 && transactionMillis > transactionThresholdMillis) {
                StringBuilder buf = new StringBuilder();
                buf.append("long time transaction, take ");
                buf.append(transactionMillis);
                buf.append(" ms : ");
                for (String sql : info.getSqlList()) {
                    buf.append(sql);
                    buf.append(";");
                }
                LOG.error(buf.toString(), new TransactionTimeoutException());
            }
        }
    
        @Override
        public String getVersion() {
            return VERSION.getVersionNumber();
        }
    
        @Override
        public JdbcDataSourceStat getDataSourceStat() {
            return dataSourceStat;
        }
    
        public Object clone() throws CloneNotSupportedException {
            return cloneDruidDataSource();
        }
    
        public DruidDataSource cloneDruidDataSource() {
            DruidDataSource x = new DruidDataSource();
    
            cloneTo(x);
    
            return x;
        }
    
        public Map<String, Object> getStatDataForMBean() {
            try {
                Map<String, Object> map = new HashMap<String, Object>();
    
                // 0 - 4
                map.put("Name", this.getName());
                map.put("URL", this.getUrl());
                map.put("CreateCount", this.getCreateCount());
                map.put("DestroyCount", this.getDestroyCount());
                map.put("ConnectCount", this.getConnectCount());
    
                // 5 - 9
                map.put("CloseCount", this.getCloseCount());
                map.put("ActiveCount", this.getActiveCount());
                map.put("PoolingCount", this.getPoolingCount());
                map.put("LockQueueLength", this.getLockQueueLength());
                map.put("WaitThreadCount", this.getNotEmptyWaitThreadPeak());
    
                // 10 - 14
                map.put("InitialSize", this.getInitialSize());
                map.put("MaxActive", this.getMaxActive());
                map.put("MinIdle", this.getMinIdle());
                map.put("PoolPreparedStatements", this.isPoolPreparedStatements());
                map.put("TestOnBorrow", this.isTestOnBorrow());
    
                // 15 - 19
                map.put("TestOnReturn", this.isTestOnReturn());
                map.put("MinEvictableIdleTimeMillis", this.minEvictableIdleTimeMillis);
                map.put("ConnectErrorCount", this.getConnectErrorCount());
                map.put("CreateTimespanMillis", this.getCreateTimespanMillis());
                map.put("DbType", this.dbType);
    
                // 20 - 24
                map.put("ValidationQuery", this.getValidationQuery());
                map.put("ValidationQueryTimeout", this.getValidationQueryTimeout());
                map.put("DriverClassName", this.getDriverClassName());
                map.put("Username", this.getUsername());
                map.put("RemoveAbandonedCount", this.getRemoveAbandonedCount());
    
                // 25 - 29
                map.put("NotEmptyWaitCount", this.getNotEmptyWaitCount());
                map.put("NotEmptyWaitNanos", this.getNotEmptyWaitNanos());
                map.put("ErrorCount", this.getErrorCount());
                map.put("ReusePreparedStatementCount", this.getCachedPreparedStatementHitCount());
                map.put("StartTransactionCount", this.getStartTransactionCount());
    
                // 30 - 34
                map.put("CommitCount", this.getCommitCount());
                map.put("RollbackCount", this.getRollbackCount());
                map.put("LastError", JMXUtils.getErrorCompositeData(this.getLastError()));
                map.put("LastCreateError", JMXUtils.getErrorCompositeData(this.getLastCreateError()));
                map.put("PreparedStatementCacheDeleteCount", this.getCachedPreparedStatementDeleteCount());
    
                // 35 - 39
                map.put("PreparedStatementCacheAccessCount", this.getCachedPreparedStatementAccessCount());
                map.put("PreparedStatementCacheMissCount", this.getCachedPreparedStatementMissCount());
                map.put("PreparedStatementCacheHitCount", this.getCachedPreparedStatementHitCount());
                map.put("PreparedStatementCacheCurrentCount", this.getCachedPreparedStatementCount());
                map.put("Version", this.getVersion());
    
                // 40 -
                map.put("LastErrorTime", this.getLastErrorTime());
                map.put("LastCreateErrorTime", this.getLastCreateErrorTime());
                map.put("CreateErrorCount", this.getCreateErrorCount());
                map.put("DiscardCount", this.getDiscardCount());
                map.put("ExecuteQueryCount", this.getExecuteQueryCount());
    
                map.put("ExecuteUpdateCount", this.getExecuteUpdateCount());
    
                return map;
            } catch (JMException ex) {
                throw new IllegalStateException("getStatData error", ex);
            }
        }
    
        public Map<String, Object> getStatData() {
            final int activeCount;
            final int activePeak;
            final Date activePeakTime;
    
            final int poolingCount;
            final int poolingPeak;
            final Date poolingPeakTime;
    
            final long connectCount;
            final long closeCount;
    
            lock.lock();
            try {
                poolingCount = this.poolingCount;
                poolingPeak = this.poolingPeak;
                poolingPeakTime = this.getPoolingPeakTime();
    
                activeCount = this.activeCount;
                activePeak = this.activePeak;
                activePeakTime = this.getActivePeakTime();
    
                connectCount = this.connectCount;
                closeCount = this.closeCount;
            } finally {
                lock.unlock();
            }
            Map<String, Object> dataMap = new LinkedHashMap<String, Object>();
    
            dataMap.put("Identity", System.identityHashCode(this));
            dataMap.put("Name", this.getName());
            dataMap.put("DbType", this.dbType);
            dataMap.put("DriverClassName", this.getDriverClassName());
    
            dataMap.put("URL", this.getUrl());
            dataMap.put("UserName", this.getUsername());
            dataMap.put("FilterClassNames", this.getFilterClassNames());
    
            dataMap.put("WaitThreadCount", this.getWaitThreadCount());
            dataMap.put("NotEmptyWaitCount", this.getNotEmptyWaitCount());
            dataMap.put("NotEmptyWaitMillis", this.getNotEmptyWaitMillis());
    
            dataMap.put("PoolingCount", poolingCount);
            dataMap.put("PoolingPeak", poolingPeak);
            dataMap.put("PoolingPeakTime", poolingPeakTime);
    
            dataMap.put("ActiveCount", activeCount);
            dataMap.put("ActivePeak", activePeak);
            dataMap.put("ActivePeakTime", activePeakTime);
    
            dataMap.put("InitialSize", this.getInitialSize());
            dataMap.put("MinIdle", this.getMinIdle());
            dataMap.put("MaxActive", this.getMaxActive());
    
            dataMap.put("QueryTimeout", this.getQueryTimeout());
            dataMap.put("TransactionQueryTimeout", this.getTransactionQueryTimeout());
            dataMap.put("LoginTimeout", this.getLoginTimeout());
            dataMap.put("ValidConnectionCheckerClassName", this.getValidConnectionCheckerClassName());
            dataMap.put("ExceptionSorterClassName", this.getExceptionSorterClassName());
    
            dataMap.put("TestOnBorrow", this.isTestOnBorrow());
            dataMap.put("TestOnReturn", this.isTestOnReturn());
            dataMap.put("TestWhileIdle", this.isTestWhileIdle());
    
            dataMap.put("DefaultAutoCommit", this.isDefaultAutoCommit());
            dataMap.put("DefaultReadOnly", this.getDefaultReadOnly());
            dataMap.put("DefaultTransactionIsolation", this.getDefaultTransactionIsolation());
    
            dataMap.put("LogicConnectCount", connectCount);
            dataMap.put("LogicCloseCount", closeCount);
            dataMap.put("LogicConnectErrorCount", this.getConnectErrorCount());
    
            dataMap.put("PhysicalConnectCount", this.getCreateCount());
            dataMap.put("PhysicalCloseCount", this.getDestroyCount());
            dataMap.put("PhysicalConnectErrorCount", this.getCreateErrorCount());
    
            dataMap.put("ExecuteCount", this.getExecuteCount());
            dataMap.put("ExecuteUpdateCount", this.getExecuteUpdateCount());
            dataMap.put("ExecuteQueryCount", this.getExecuteQueryCount());
            dataMap.put("ExecuteBatchCount", this.getExecuteBatchCount());
            dataMap.put("ErrorCount", this.getErrorCount());
            dataMap.put("CommitCount", this.getCommitCount());
            dataMap.put("RollbackCount", this.getRollbackCount());
    
            dataMap.put("PSCacheAccessCount", this.getCachedPreparedStatementAccessCount());
            dataMap.put("PSCacheHitCount", this.getCachedPreparedStatementHitCount());
            dataMap.put("PSCacheMissCount", this.getCachedPreparedStatementMissCount());
    
            dataMap.put("StartTransactionCount", this.getStartTransactionCount());
            dataMap.put("TransactionHistogram", this.getTransactionHistogramValues());
    
            dataMap.put("ConnectionHoldTimeHistogram", this.getDataSourceStat().getConnectionHoldHistogram().toArray());
            dataMap.put("RemoveAbandoned", this.isRemoveAbandoned());
            dataMap.put("ClobOpenCount", this.getDataSourceStat().getClobOpenCount());
            dataMap.put("BlobOpenCount", this.getDataSourceStat().getBlobOpenCount());
            dataMap.put("KeepAliveCheckCount", this.getDataSourceStat().getKeepAliveCheckCount());
    
            dataMap.put("KeepAlive", this.isKeepAlive());
            dataMap.put("FailFast", this.isFailFast());
            dataMap.put("MaxWait", this.getMaxWait());
            dataMap.put("MaxWaitThreadCount", this.getMaxWaitThreadCount());
            dataMap.put("PoolPreparedStatements", this.isPoolPreparedStatements());
            dataMap.put("MaxPoolPreparedStatementPerConnectionSize", this.getMaxPoolPreparedStatementPerConnectionSize());
            dataMap.put("MinEvictableIdleTimeMillis", this.minEvictableIdleTimeMillis);
            dataMap.put("MaxEvictableIdleTimeMillis", this.maxEvictableIdleTimeMillis);
    
            dataMap.put("LogDifferentThread", isLogDifferentThread());
            dataMap.put("RecycleErrorCount", getRecycleErrorCount());
            dataMap.put("PreparedStatementOpenCount", getPreparedStatementCount());
            dataMap.put("PreparedStatementClosedCount", getClosedPreparedStatementCount());
    
            dataMap.put("UseUnfairLock", isUseUnfairLock());
            dataMap.put("InitGlobalVariants", isInitGlobalVariants());
            dataMap.put("InitVariants", isInitVariants());
            return dataMap;
        }
    
        public JdbcSqlStat getSqlStat(int sqlId) {
            return this.getDataSourceStat().getSqlStat(sqlId);
        }
    
        public JdbcSqlStat getSqlStat(long sqlId) {
            return this.getDataSourceStat().getSqlStat(sqlId);
        }
    
        public Map<String, JdbcSqlStat> getSqlStatMap() {
            return this.getDataSourceStat().getSqlStatMap();
        }
    
        public Map<String, Object> getWallStatMap() {
            WallProviderStatValue wallStatValue = getWallStatValue(false);
    
            if (wallStatValue != null) {
                return wallStatValue.toMap();
            }
    
            return null;
        }
    
        public WallProviderStatValue getWallStatValue(boolean reset) {
            for (Filter filter : this.filters) {
                if (filter instanceof WallFilter) {
                    WallFilter wallFilter = (WallFilter) filter;
                    return wallFilter.getProvider().getStatValue(reset);
                }
            }
    
            return null;
        }
    
        public Lock getLock() {
            return lock;
        }
    
        @Override
        public boolean isWrapperFor(Class<?> iface) {
            for (Filter filter : this.filters) {
                if (filter.isWrapperFor(iface)) {
                    return true;
                }
            }
    
            if (this.statLogger != null
                && (this.statLogger.getClass() == iface || DruidDataSourceStatLogger.class == iface)) {
                return true;
            }
    
            return super.isWrapperFor(iface);
        }
    
        @SuppressWarnings("unchecked")
        public <T> T unwrap(Class<T> iface) {
            for (Filter filter : this.filters) {
                if (filter.isWrapperFor(iface)) {
                    return (T) filter;
                }
            }
    
            if (this.statLogger != null
                && (this.statLogger.getClass() == iface || DruidDataSourceStatLogger.class == iface)) {
                return (T) statLogger;
            }
    
            return super.unwrap(iface);
        }
    
        public boolean isLogDifferentThread() {
            return logDifferentThread;
        }
    
        public void setLogDifferentThread(boolean logDifferentThread) {
            this.logDifferentThread = logDifferentThread;
        }
    
        public DruidPooledConnection tryGetConnection() throws SQLException {
            if (poolingCount == 0) {
                return null;
            }
            return getConnection();
        }
    
        @Override
        public int fill() throws SQLException {
            return this.fill(this.maxActive);
        }
    
        @Override
        public int fill(int toCount) throws SQLException {
            if (closed) {
                throw new DataSourceClosedException("dataSource already closed at " + new Date(closeTimeMillis));
            }
    
            if (toCount < 0) {
                throw new IllegalArgumentException("toCount can't not be less than zero");
            }
    
            init();
    
            if (toCount > this.maxActive) {
                toCount = this.maxActive;
            }
    
            int fillCount = 0;
            for (;;) {
                try {
                    lock.lockInterruptibly();
                } catch (InterruptedException e) {
                    connectErrorCountUpdater.incrementAndGet(this);
                    throw new SQLException("interrupt", e);
                }
    
                boolean fillable = this.isFillable(toCount);
    
                lock.unlock();
    
                if (!fillable) {
                    break;
                }
    
                DruidConnectionHolder holder;
                try {
                    PhysicalConnectionInfo pyConnInfo = createPhysicalConnection();
                    holder = new DruidConnectionHolder(this, pyConnInfo);
                } catch (SQLException e) {
                    LOG.error("fill connection error, url: " + this.jdbcUrl, e);
                    connectErrorCountUpdater.incrementAndGet(this);
                    throw e;
                }
    
                try {
                    lock.lockInterruptibly();
                } catch (InterruptedException e) {
                    connectErrorCountUpdater.incrementAndGet(this);
                    throw new SQLException("interrupt", e);
                }
    
                try {
                    if (!this.isFillable(toCount)) {
                        JdbcUtils.close(holder.getConnection());
                        LOG.info("fill connections skip.");
                        break;
                    }
                    this.putLast(holder, System.currentTimeMillis());
                    fillCount++;
                } finally {
                    lock.unlock();
                }
            }
    
            if (LOG.isInfoEnabled()) {
                LOG.info("fill " + fillCount + " connections");
            }
    
            return fillCount;
        }
    
        private boolean isFillable(int toCount) {
            int currentCount = this.poolingCount + this.activeCount;
            if (currentCount >= toCount || currentCount >= this.maxActive) {
                return false;
            } else {
                return true;
            }
        }
    
        public boolean isFull() {
            lock.lock();
            try {
                return this.poolingCount + this.activeCount >= this.maxActive;
            } finally {
                lock.unlock();
            }
        }
    
        private void emptySignal() {
            if (createScheduler == null) {
                empty.signal();
                return;
            }
    
            if (createTaskCount >= maxCreateTaskCount) {
                return;
            }
    
            if (activeCount + poolingCount + createTaskCount >= maxActive) {
                return;
            }
    
            createTaskCount++;
            CreateConnectionTask task = new CreateConnectionTask();
            this.createSchedulerFuture = createScheduler.submit(task);
        }
    
        @Override
        public ObjectName preRegister(MBeanServer server, ObjectName name) throws Exception {
            if (server != null) {
                try {
                    if (server.isRegistered(name)) {
                        server.unregisterMBean(name);
                    }
                } catch (Exception ex) {
                    LOG.warn("DruidDataSource preRegister error", ex);
                }
            }
            return name;
        }
    
        @Override
        public void postRegister(Boolean registrationDone) {
    
        }
    
        @Override
        public void preDeregister() throws Exception {
    
        }
    
        @Override
        public void postDeregister() {
    
        }
    
        public boolean isClosed() {
            return this.closed;
        }
    }

### 参考阅读 ###

[Java魔法类：Unsafe应用解析][Java_Unsafe]

[面试官：说说 Java 中的 Unsafe 和 CAS][Java _ Unsafe _ CAS]

[sun.misc.Unsafe.park(Native Method)异常][sun.misc.Unsafe.park_Native Method]

[深入理解sun.misc.Unsafe原理][sun.misc.Unsafe]

[Link 1]: https://baike.baidu.com/item/%E6%95%B0%E6%8D%AE%E5%BA%93
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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Jvb255YQ_size_16_color_FFFFFF_t_70 1]: /images/20221123/6cd9f2c8f2c1450daeaf19ce6fb617ab.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Jvb255YQ_size_16_color_FFFFFF_t_70 2]: /images/20221123/26d16e5974e149e4ac5334a643a133d2.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Jvb255YQ_size_16_color_FFFFFF_t_70 3]: /images/20221123/fd16e9317d07408fbf4b7d92f7b6668c.png
[20200918094215700.png]: /images/20221123/368a57a15f4446429261db045d55c984.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Jvb255YQ_size_16_color_FFFFFF_t_70 4]: /images/20221123/32c260356c9b49b38e60fc43c1f5e5f3.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Jvb255YQ_size_16_color_FFFFFF_t_70 5]: /images/20221123/90e6079f48a64514941372a89cb10ec5.png
[https_github.com_alibaba_druid]: https://github.com/alibaba/druid
[RDS_mysql]: https://github.com/alibaba/druid/issues/1084
[Java_Unsafe]: https://tech.meituan.com/2019/02/14/talk-about-java-magic-class-unsafe.html
[Java _ Unsafe _ CAS]: https://zhuanlan.zhihu.com/p/212311781
[sun.misc.Unsafe.park_Native Method]: https://blog.csdn.net/weixin_41160551/article/details/97758053
[sun.misc.Unsafe]: https://blog.csdn.net/zyzzxycj/article/details/89877863?utm_medium=distribute.pc_relevant.none-task-blog-BlogCommendFromMachineLearnPai2-1.edu_weight&depth_1-utm_source=distribute.pc_relevant.none-task-blog-BlogCommendFromMachineLearnPai2-1.edu_weight