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：github.com/baidu/uid-g…

（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

    com.xfvape.uid
    uid-generator
    0.0.4-RELEASE

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：

    com.xfvape.uid
    uid-generator
    0.0.4-RELEASE
    
        
                org.slf4j
                log4j-over-slf4j
        
        
                ch.qos.logback
                logback-classic
        
        
                org.slf4j
                slf4j-api
        
         
                org.mybatis
                mybatis-spring
        
        
                org.mybatis
                mybatis
        
    

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"?>


  
    
    
    
    
    
    
    
  

  
        INSERT INTO WORKER_NODE
        (HOST_NAME,
         PORT,
         TYPE,
         LAUNCH_DATE,
         MODIFIED,
         CREATED)
        VALUES (
           #{hostName},
           #{port},
           #{type},
           #{launchDate},
           NOW(),
           NOW())
    

  
        SELECT
            ID,
            HOST_NAME,
            PORT,
            TYPE,
            LAUNCH_DATE,
            MODIFIED,
            CREATED
        FROM
            WORKER_NODE
        WHERE
            HOST_NAME = #{host} AND PORT = #{port}
    

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

项目目录结构