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
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
3.9 访问接口测试
http://127.0.0.1:8099/test/baidu/uid