转载 https://mp.weixin.qq.com/s/I9MnjiYasPqiKWVFdSUOjw
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
解决了时钟回调的问题
使用ringbuffer,无锁进行id的生产与消费,速度非常快
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。
Spring Boot 基础就不介绍了，新手请看这个学习教程和示例仓库：https://github.com/javastacks/spring-boot-best-practice
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;
报错信息如下:
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。MySQL 开发的 36 条军规建议看看。
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
项目目录结构
