springboot mybatis使用redis作为二级缓存

朱雀 2023-06-25 03:03 59阅读 0赞

创建springboot项目引入如下依赖

<dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-data-redis</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter</artifactId>
            </dependency>
    
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>fastjson</artifactId>
                <version>1.2.8</version>
            </dependency>
    
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>1.1.1</version>
            </dependency>
            <dependency>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-core</artifactId>
                <version>1.3.4</version>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-devtools</artifactId>
                <optional>true</optional>
            </dependency>
    
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid</artifactId>
                <version>1.1.14</version>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
               <version>5.1.42</version>
            </dependency>
           
    
            
    
        </dependencies>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
                <plugin>
                    <groupId>org.mybatis.generator</groupId>
                    <artifactId>mybatis-generator-maven-plugin</artifactId>
                    <version>1.3.2</version>
                    <configuration>
                        <configurationFile>src/main/resources/generatorConfig.xml</configurationFile>
                        <verbose>true</verbose>
                        <overwrite>true</overwrite>
                    </configuration>
                </plugin>
            </plugins>
        </build>

application.properties配置

server.port=8081
    spring.redis.database=0
    spring.redis.host=127.0.0.1
    spring.redis.port=6379
    spring.redis.jedis.pool.max-active=100
    spring.redis.jedis.pool.max-idle=8
    spring.redis.jedis.pool.max-wait=-1ms
    spring.redis.jedis.pool.min-idle=0
    spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
    spring.datasource.driver-class-name=com.mysql.jdbc.Driver
    spring.datasource.url=jdbc:mysql://localhost:3306/fruit?useUnicode=true&characterEncoding=utf8
    spring.datasource.username=root
    spring.datasource.password=admin
    spring.datasource.sql-script-encoding=UTF-8
    mybatis.type-aliases-package=com.example.demo.pojo
    mybatis.mapper-locations=classpath:mappers/*.xml

在resources目录下创建自动生成配置文件generatorConfig.xml

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE generatorConfiguration
            PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
            "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
    
    <generatorConfiguration>
        <classPathEntry
                location="D:/mysql-connector-java-5.1.22-bin.jar"/>
        <context id="my" targetRuntime="MyBatis3">
            <commentGenerator>
                <property name="suppressDate" value="false"/>
                <property name="suppressAllComments" value="true"/>
            </commentGenerator>
            <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                            connectionURL="jdbc:mysql://localhost:3306/fruit" userId="root"
                            password="admin"/>
    
            <javaModelGenerator targetPackage="com.example.demo.pojo"
                                targetProject="C:\Users\wangsheng\Desktop\广电\DVB\demo\src\main\java">
                <property name="enableSubPackages" value="true"/>
                <property name="trimStrings" value="true"/>
            </javaModelGenerator>
    
            <sqlMapGenerator targetPackage="mappers"
                             targetProject="C:\Users\wangsheng\Desktop\广电\DVB\demo\src\main\resources">
                <property name="enableSubPackages" value="true"/>
            </sqlMapGenerator>
    
            <javaClientGenerator targetPackage="com.example.demo.mapper"
                                 targetProject="C:\Users\wangsheng\Desktop\广电\DVB\demo\src\main\java" type="XMLMAPPER">
                <property name="enableSubPackages" value="true"/>
            </javaClientGenerator>
    
            <table tableName="book" domainObjectName=""
                   enableCountByExample="false" enableUpdateByExample="false"
                   enableDeleteByExample="false" enableSelectByExample="false"
                   selectByExampleQueryId="false">
            </table>
    
    
        </context>
    </generatorConfiguration>

自动生成后的文件目录

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xldHRlcnNz_size_16_color_FFFFFF_t_70][]

BookMapper接口加上@Repository注解，实体类要实现序列化Serializable，不然存不到redis

编写Service

package com.example.demo.service;
    
    import com.example.demo.pojo.Book;
    
    /**
     * @Author: wangsheng
     * @Description:
     * @CreateDate: 2019/12/24 16:14
     */
    
    public interface bookService {
    
       
        
        public void update(Book book);
    
        public Book select(int id);
    
    }

ServiceImpl

package com.example.demo.service;
    
    import com.example.demo.mapper.BookMapper;
    import com.example.demo.pojo.Book;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    /**
     * @Author: wangsheng
     * @Description:
     * @CreateDate: 2019/12/24 16:14
     */
    @Service
    public class bookServiceImpl implements bookService {
        @Autowired
        BookMapper bookMapper;
    
    
        public void update(Book book) {
            bookMapper.updateByPrimaryKeySelective(book);
        }
    
        public Book select(int id) {
            return bookMapper.selectByPrimaryKey(id);
        }
    }

Controller

package com.example.demo.controller;
    
    import com.example.demo.pojo.Book;
    
    import com.example.demo.service.bookService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.PathVariable;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    
    /**
     * @Author: wangsheng
     * @Description:
     * @CreateDate: 2019/12/24 16:25
     */
    @RestController
    public class bookController {
        @Autowired
       bookService bookService;
        
        @RequestMapping("/select/{id}")
        public Book select(@PathVariable Integer id)
        {
            System.out.println("查询结果"+id);
            Book book=bookService.select(id);
            return book;
        }
        @RequestMapping("/update/{id}/{name}")
        public void update(@PathVariable Integer id, @PathVariable String name){
          Book book=new Book();
          book.setId(id);
          book.setName(name);
         bookService.update(book);
            System.out.println("更新了");
        }
    }

建立获取spring容器获取bean工具类，通过Spring Aware（容器感知）来获取到ApplicationContext，然后根据ApplicationContext获取容器中的Bean，因为RedisTemplate的bean不能用@Autowired注解注入

import org.springframework.context.ApplicationContext;
    import org.springframework.context.ApplicationContextAware;
    import org.springframework.stereotype.Component;
    
    /**
     * @Author: wangsheng
     * @Description:
     * @CreateDate: 2019/12/24 16:51
     */
    @Component
    public class ApplicationContextHolder implements ApplicationContextAware {
        private static ApplicationContext applicationContext;
    
        /**
         * 实现ApplicationContextAware接口的context注入函数, 将其存入静态变量.
         */
        public void setApplicationContext(ApplicationContext applicationContext) {
            ApplicationContextHolder.applicationContext = applicationContext; // NOSONAR
        }
    
        /**
         * 取得存储在静态变量中的ApplicationContext.
         */
        public static ApplicationContext getApplicationContext() {
            checkApplicationContext();
            return applicationContext;
        }
    
        /**
         * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
         */
        @SuppressWarnings("unchecked")
        public static <T> T getBean(String name) {
            checkApplicationContext();
            return (T) applicationContext.getBean(name);
        }
    
        /**
         * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
         */
        @SuppressWarnings("unchecked")
        public static <T> T getBean(Class<T> clazz) {
            checkApplicationContext();
            return (T) applicationContext.getBeansOfType(clazz);
        }
    
        /**
         * 清除applicationContext静态变量.
         */
        public static void cleanApplicationContext() {
            applicationContext = null;
        }
    
        private static void checkApplicationContext() {
            if (applicationContext == null) {
                throw new IllegalStateException("applicaitonContext未注入,请在applicationContext.xml中定义SpringContextHolder");
            }
        }
    
    
    }

mybatis缓存接口

import java.util.concurrent.locks.ReadWriteLock;
    
    /**
     * @Author: wangsheng
     * @Description:
     * @CreateDate: 2019/12/24 15:59
     */
    public interface Cache {
        String getId();
    
        int getSize();
    
        void putObject(Object key, Object value);
    
        Object getObject(Object key);
    
        Object removeObject(Object key);
    
        void clear();
    
        ReadWriteLock getReadWriteLock();
    
    }

实现mybatis缓存接口

import org.apache.ibatis.cache.Cache;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.data.redis.core.RedisCallback;
    import org.springframework.data.redis.core.RedisTemplate;
    import org.springframework.data.redis.core.ValueOperations;
    
    import java.util.concurrent.TimeUnit;
    import java.util.concurrent.locks.ReadWriteLock;
    import java.util.concurrent.locks.ReentrantReadWriteLock;
    
    
    /**
     * @Author: wangsheng
     * @Description:
     * @CreateDate: 2019/12/24 15:56
     */
    
    public class RedisCache implements Cache { //slf4j的日志记录器
        private static final Logger logger = LoggerFactory.getLogger(RedisCache.class);
        private final ReadWriteLock readWriteLock = new ReentrantReadWriteLock();
        private final String id;  // cache instance id
        private RedisTemplate redisTemplate;
        private static final long EXPIRE_TIME_IN_MINUTES = 30; // redis过期时间
        public RedisCache(String id) {
            if (id == null) {
                throw new IllegalArgumentException("Cache instances require an ID");
            }
            this.id = id;
        }
        @Override
        public String getId() {
            return id;
        }
        /**
         * Put query result to redis
         *
         * @param key
         * @param value
         */
        @Override
        @SuppressWarnings("unchecked")
        public void putObject(Object key, Object value) {
            RedisTemplate redisTemplate = getRedisTemplate();
            ValueOperations opsForValue = redisTemplate.opsForValue();
            opsForValue.set(key, value, EXPIRE_TIME_IN_MINUTES, TimeUnit.MINUTES);
            logger.debug("Put query result to redis");
        }
        /**
         * Get cached query result from redis
         *
         * @param key
         * @return
         */
        @Override
        public Object getObject(Object key) {
            RedisTemplate redisTemplate = getRedisTemplate();
            ValueOperations opsForValue = redisTemplate.opsForValue();
            logger.debug("Get cached query result from redis");
            return opsForValue.get(key);
        }
        /**
         * Remove cached query result from redis
         *
         * @param key
         * @return
         */
        @Override
        @SuppressWarnings("unchecked")
        public Object removeObject(Object key) {
            RedisTemplate redisTemplate = getRedisTemplate();
            redisTemplate.delete(key);
            logger.debug("Remove cached query result from redis");
            return null;
        }
        /**
         * Clears this cache instance
         */
        @Override
        public void clear() {
            RedisTemplate redisTemplate = getRedisTemplate();
            redisTemplate.execute((RedisCallback) connection -> {
                connection.flushDb();
                return null;
            });
            logger.debug("Clear all the cached query result from redis");
        }
        @Override
        public int getSize() {
            return 0;
        }
        @Override
        public ReadWriteLock getReadWriteLock() {
            return readWriteLock;
        }
        private RedisTemplate getRedisTemplate() {
            if (redisTemplate == null) {
                redisTemplate = ApplicationContextHolder.getBean("redisTemplate");
            }
            return redisTemplate;
        }
    
    }

在mapper.xml映射文件中开启缓存

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
    <mapper namespace="com.example.demo.mapper.BookMapper">
      <resultMap id="BaseResultMap" type="com.example.demo.pojo.Book">
        <id column="id" jdbcType="INTEGER" property="id" />
        <result column="name" jdbcType="VARCHAR" property="name" />
        <result column="price" jdbcType="DOUBLE" property="price" />
        <result column="updatetime" jdbcType="VARCHAR" property="updatetime" />
        <result column="image" jdbcType="VARCHAR" property="image" />
        <result column="code" jdbcType="INTEGER" property="code" />
        <result column="type" jdbcType="INTEGER" property="type" />
        <result column="jieshao" jdbcType="VARCHAR" property="jieshao" />
      </resultMap>
      <cache eviction="LRU" flushInterval="120000" size="1024" readOnly="true" type="com.example.demo.util.RedisCache"/>
      <sql id="Base_Column_List">
        id, name, price, updatetime, image, code, type, jieshao
      </sql>
      <select id="selectByPrimaryKey" parameterType="java.lang.Integer" resultMap="BaseResultMap">
        select
        <include refid="Base_Column_List" />
        from book
        where id = #{id,jdbcType=INTEGER}
      </select>
    
      <update id="updateByPrimaryKeySelective" parameterType="com.example.demo.pojo.Book" >
        update book
        <set>
          <if test="name != null">
            name = #{name,jdbcType=VARCHAR},
          </if>
          <if test="price != null">
            price = #{price,jdbcType=DOUBLE},
          </if>
          <if test="updatetime != null">
            updatetime = #{updatetime,jdbcType=VARCHAR},
          </if>
          <if test="image != null">
            image = #{image,jdbcType=VARCHAR},
          </if>
          <if test="code != null">
            code = #{code,jdbcType=INTEGER},
          </if>
          <if test="type != null">
            type = #{type,jdbcType=INTEGER},
          </if>
          <if test="jieshao != null">
            jieshao = #{jieshao,jdbcType=VARCHAR},
          </if>
        </set>
        where id = #{id,jdbcType=INTEGER}
      </update>
    
    
      <update id="updateByPrimaryKey" parameterType="com.example.demo.pojo.Book">
        update book
        set name = #{name,jdbcType=VARCHAR},
          price = #{price,jdbcType=DOUBLE},
          updatetime = #{updatetime,jdbcType=VARCHAR},
          image = #{image,jdbcType=VARCHAR},
          code = #{code,jdbcType=INTEGER},
          type = #{type,jdbcType=INTEGER},
          jieshao = #{jieshao,jdbcType=VARCHAR}
        where id = #{id,jdbcType=INTEGER}
      </update>
    </mapper>

在启动类上开启缓存和Mapper扫描

@SpringBootApplication
    @MapperScan(basePackages = "com.example.demo.mapper")
    @EnableCaching
    public class DemoApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(DemoApplication.class, args);
        }
    
    }

启动项目，访问[http://localhost:8081/select/1][http_localhost_8081_select_1] 会将结果存到redis，再次访问从redis里面读取。

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xldHRlcnNz_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20191224211243623.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xldHRlcnNz,size_16,color_FFFFFF,t_70
[http_localhost_8081_select_1]: http://localhost:8081/select/1