百度开源的一款分布式高性能的唯一ID生成器，非常强大！

亦凉 2022-10-15 00:49 85阅读 0赞

![d4990eae942252f55a5bfbc946fd834b.png][]

*来源：https://lilinchao.com/archives/1226.html*

### 一、UidGenerator是什么 ###

UidGenerator是百度开源的一款分布式高性能的唯一ID生成器，是基于snowflake模型的一种ID生成器

### 二、UidGenerator的优势 ###

1.  解决了时钟回调的问题
2.  使用ringbuffer,无锁进行id的生产与消费,速度非常快
3.  适用于多线程,不会有单线程瓶颈

### 三、整合 ###

本次通过SpringBoot2.x和MyBatis对百度UidGenerator进行整合。

**3.1 UidGenerator引入**

**一般使用两种方式引入UidGenerator:**

（1）从官网下载源码作为自己项目的一个Module引入到项目中

官网地址：https://github.com/baidu/uid-generator/blob/master/README.zh\_cn.md

（2）互联网jar包引入（本文采取的是该种方式）

因为UidGenerator自带引入了mybatis，和自己项目有冲突的可以进行排除

<dependency>
        <groupId>com.xfvape.uid</groupId>
        <artifactId>uid-generator</artifactId>
        <version>0.0.4-RELEASE</version>
    </dependency>

排除冲突依赖

uid-generator中依赖了logback和mybatis。一般在项目搭建过程中，springboot中已经有了logback依赖，mybatis会作为单独的依赖引入。如果版本和uid-generator中的依赖不一致的话，就会导致冲突。

排除冲突的依赖如下：

<dependency>
        <groupId>com.xfvape.uid</groupId>
        <artifactId>uid-generator</artifactId>
        <version>0.0.4-RELEASE</version>
        <exclusions>
                    <exclusion>
                        <groupId>org.slf4j</groupId>
                        <artifactId>log4j-over-slf4j</artifactId>
                    </exclusion>
                    <exclusion>
                        <groupId>ch.qos.logback</groupId>
                        <artifactId>logback-classic</artifactId>
                    </exclusion>
                    <exclusion>
                        <groupId>org.slf4j</groupId>
                        <artifactId>slf4j-api</artifactId>
                    </exclusion>
                     <exclusion>
                        <groupId>org.mybatis</groupId>
                        <artifactId>mybatis-spring</artifactId>
                    </exclusion>
                    <exclusion>
                        <groupId>org.mybatis</groupId>
                        <artifactId>mybatis</artifactId>
                    </exclusion>
        </exclusions>
    </dependency>

**3.2 创建表**

在 MySQL数据库中建一个名为 `WORKER_NODE`的数据表，其 sql如下：

CREATE TABLE WORKER_NODE
    (
    ID BIGINT NOT NULL AUTO_INCREMENT COMMENT 'auto increment id',
    HOST_NAME VARCHAR(64) NOT NULL COMMENT 'host name',
    PORT VARCHAR(64) NOT NULL COMMENT 'port',
    TYPE INT NOT NULL COMMENT 'node type: ACTUAL or CONTAINER',
    LAUNCH_DATE DATE NOT NULL COMMENT 'launch date',
    MODIFIED TIMESTAMP NOT NULL COMMENT 'modified time',
    CREATED TIMESTAMP NOT NULL COMMENT 'created time',
    PRIMARY KEY(ID)
    )
     COMMENT='DB WorkerID Assigner for UID Generator',ENGINE = INNODB;

建表时可能会报错，原因是该建表语句定义了两个TIMESTAMP字段，因为mysql 低版本控制比较严格

解决办法：

**方式一：**

直接把TIMESTAMP改成DATETIME 即可

**方式二：**

建表前先设置sql\_mode：

set sql_mode="NO_ENGINE_SUBSTITUTION";

**3.3 将uid-generator核心对象装配为spring的bean**

uid-generator提供了两种生成器: DefaultUidGenerator、CachedUidGenerator。如对UID生成性能有要求, 请使用CachedUidGenerator。

@Configuration
    public class WorkerNodeConfig {
    
        @Bean("disposableWorkerIdAssigner")
        public DisposableWorkerIdAssigner disposableWorkerIdAssigner(){
            DisposableWorkerIdAssigner disposableWorkerIdAssigner = new DisposableWorkerIdAssigner();
            return  disposableWorkerIdAssigner;
        }
    
        @Bean("cachedUidGenerator")
        public UidGenerator uidGenerator(DisposableWorkerIdAssigner disposableWorkerIdAssigner){
            CachedUidGenerator cachedUidGenerator = new CachedUidGenerator();
            cachedUidGenerator.setWorkerIdAssigner(disposableWorkerIdAssigner);
            return cachedUidGenerator;
        }
    }

直接创建WorkerNodeConfig类，复制以上代码。

**3.4 重写WorkerIdAssigner接口**

public class DisposableWorkerIdAssigner implements WorkerIdAssigner {
    
        @Resource
        private WorkerNodeMapper workerNodeMapper;
        @Override
        @Transactional
        public long assignWorkerId() {
            WorkerNode workerNode = buildWorkerNode();
    
            workerNodeMapper.addWorkerNode(workerNode);
    
            return workerNode.getId();
        }
    
        private WorkerNode buildWorkerNode() {
            WorkerNode workNode = new WorkerNode();
            if (DockerUtils.isDocker()) {
                workNode.setType(WorkerNodeType.CONTAINER.value());
                workNode.setHostName(DockerUtils.getDockerHost());
                workNode.setPort(DockerUtils.getDockerPort());
                workNode.setLaunchDate(new Date());
            } else {
                workNode.setType(WorkerNodeType.ACTUAL.value());
                workNode.setHostName(NetUtils.getLocalAddress());
                workNode.setPort(System.currentTimeMillis() + "-" + RandomUtils.nextInt(100000));
                workNode.setLaunchDate(new Date());
            }
    
            return workNode;
        }
    }

创建一个DisposableWorkerIdAssigner类直接复制以上代码。

**3.5 引入WorkerNodeMapper.xml**

<?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.uidgenerator.mapper.WorkerNodeMapper">
      <resultMap id="BaseResultMap"
                 type="com.uidgenerator.entity.WorkerNode">
        <id column="ID" jdbcType="BIGINT" property="id" />
        <result column="HOST_NAME" jdbcType="VARCHAR" property="hostName" />
        <result column="PORT" jdbcType="VARCHAR" property="port" />
        <result column="TYPE" jdbcType="INTEGER" property="type" />
        <result column="LAUNCH_DATE" jdbcType="DATE" property="launchDate" />
        <result column="MODIFIED" jdbcType="TIMESTAMP" property="modified" />
        <result column="CREATED" jdbcType="TIMESTAMP" property="created" />
      </resultMap>
    
      <insert id="addWorkerNode" useGeneratedKeys="true" keyProperty="id"
              parameterType="com.uidgenerator.entity.WorkerNode">
            INSERT INTO WORKER_NODE
            (HOST_NAME,
             PORT,
             TYPE,
             LAUNCH_DATE,
             MODIFIED,
             CREATED)
            VALUES (
                       #{hostName},
                       #{port},
                       #{type},
                       #{launchDate},
                       NOW(),
                       NOW())
        </insert>
    
      <select id="getWorkerNodeByHostPort" resultMap="BaseResultMap ">
            SELECT
                ID,
                HOST_NAME,
                PORT,
                TYPE,
                LAUNCH_DATE,
                MODIFIED,
                CREATED
            FROM
                WORKER_NODE
            WHERE
                HOST_NAME = #{host} AND PORT = #{port}
        </select>
    </mapper>

可以通过mybatis生成工具直接生成文件和实体类，然后将插入和查询方法复制

注意修改resultMap中的type和insert中的keyProperty为自身项目的实体类地址

**在application.yml文件中增加如下配置**

mybatis:
      mapper-locations: classpath:mybatis/*.xml

**3.6实体类**

使用插件生成的实体类

**3.7创建Mapper**

@Mapper
    public interface WorkerNodeMapper {
    
        int addWorkerNode(WorkerNode workerNodeEntity);
    
    
        WorkerNode getWorkerNodeByHostPort(@Param("host") String host, @Param("port") String port);
    
    }

**3.8 Service**

IWorkerNodeService接口

public interface IWorkerNodeService {
        public long genUid();
    }

WorkerNodeServiceImpl实现类

@Service
    public class WorkerNodeServiceImpl implements IWorkerNodeService {
        @Resource
        private UidGenerator uidGenerator;
    
        @Override
        public long genUid() {
            Long uu\_id = UidGeneratorComponent.uu\_id;
            return uidGenerator.getUID();
        }
    }

**3.8 Controller**

@RestController
    public class WorkerNodeServiceController {
        @Resource
        private IWorkerNodeService workerNodeService;
        /**
         * 集成百度uid-generator生成id
         * @return
         */
        @GetMapping("/baidu/uid")
        public long baiduUid(){
            long uid = workerNodeService.genUid();
            return uid;
        }
    }

3.9 访问接口测试

http://127.0.0.1:8099/test/baidu/uid

![702296d45e509290de8bb835e680286a.png][]

**项目目录结构**

![0fcac1073053d38ef43e8ca4470b4750.png][]

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