流水号生成器(全局唯一 ID生成器)是服务化系统的基础设施,其在保障系统的正确运行和高可用方面发挥着重要作用。而关于流水号生成算法首屈一指的当属 Snowflake雪花算法,然而 Snowflake本身很难在现实项目中直接使用,因此实际应用时需要一种可落地的方案。
Snowflake仓库
https://github.com/twitter/snowflake
UidGenerator 由百度用Java语言开发的, 基于 Snowflake算法的唯一ID生成器。UidGenerator以组件形式工作在应用项目中, 支持自定义workerId位数和初始化策略, 从而适用于docker等虚拟化环境下实例自动重启、漂移等场景。
UidGenerator仓库
https://github.com/baidu/uid-generator
UidGenerator中文文档
https://github.com/baidu/uid-generator/blob/master/README.zh_cn.md
0x01:先在 pom.xml中添加相关依赖
<dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>1.3.2</version> </dependency> <!--for Mysql--> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <scope>runtime</scope> <version>8.0.12</version> </dependency> <!-- druid --> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid-spring-boot-starter</artifactId> <version>1.1.9</version> </dependency> <!--必须放在最后--> <dependency> <groupId>cn.codesheep</groupId> <artifactId>uid-generator</artifactId> <version>1.0</version> </dependency> </dependencies>
0x02: application.properties配置文件中添加配置(主要是 MySQL和 MyBatis配置)
server.port=9999 spring.datasource.url=jdbc:mysql://xxx.xxx.xxx.xxx:3306/xxx?useUnicode=true&characterEncoding=utf-8&useSSL=false spring.datasource.username=root spring.datasource.password=xxx spring.datasource.driver-class-name=com.mysql.jdbc.Driver mybatis.mapper-locations=classpath:mapper/*.xml mybatis.configuration.map-underscore-to-camel-case=true
0x03:创建数据库表
运行sql脚本以导入表WORKER_NODE, 脚本如下
DROP DATABASE IF EXISTS `xxxx`; CREATE DATABASE `xxxx` ; use `xxxx`; DROP TABLE IF EXISTS WORKER_NODE; 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;
0x04:Spring配置
提供了两种生成器: DefaultUidGenerator、CachedUidGenerator。如对UID生成性能有要求, 请使用CachedUidGenerator
对应Spring配置分别为: default-uid-spring.xml、cached-uid-spring.xml
DefaultUidGenerator配置
<!-- DefaultUidGenerator --> <bean id="defaultUidGenerator" class="com.baidu.fsg.uid.impl.DefaultUidGenerator" lazy-init="false"> <property name="workerIdAssigner" ref="disposableWorkerIdAssigner"/> <!-- Specified bits & epoch as your demand. No specified the default value will be used --> <property name="timeBits" value="29"/> <property name="workerBits" value="21"/> <property name="seqBits" value="13"/> <property name="epochStr" value="2016-09-20"/> </bean> <!-- 用完即弃的WorkerIdAssigner,依赖DB操作 --> <bean id="disposableWorkerIdAssigner" class="com.baidu.fsg.uid.worker.DisposableWorkerIdAssigner" />
CachedUidGenerator配置
<!-- CachedUidGenerator --> <bean id="cachedUidGenerator" class="com.baidu.fsg.uid.impl.CachedUidGenerator"> <property name="workerIdAssigner" ref="disposableWorkerIdAssigner" /> <!-- 以下为可选配置, 如未指定将采用默认值 --> <!-- Specified bits & epoch as your demand. No specified the default value will be used --> <property name="timeBits" value="29"/> <property name="workerBits" value="21"/> <property name="seqBits" value="13"/> <property name="epochStr" value="2016-09-20"/> <!-- RingBuffer size扩容参数, 可提高UID生成的吞吐量. --> <!-- 默认:3, 原bufferSize=8192, 扩容后bufferSize= 8192 << 3 = 65536 --> <property name="boostPower" value="3"></property> <!-- 指定何时向RingBuffer中填充UID, 取值为百分比(0, 100), 默认为50 --> <!-- 举例: bufferSize=1024, paddingFactor=50 -> threshold=1024 * 50 / 100 = 512. --> <!-- 当环上可用UID数量 < 512时, 将自动对RingBuffer进行填充补全 --> <property name="paddingFactor" value="50"></property> <!-- 另外一种RingBuffer填充时机, 在Schedule线程中, 周期性检查填充 --> <!-- 默认:不配置此项, 即不实用Schedule线程. 如需使用, 请指定Schedule线程时间间隔, 单位:秒 --> <property name="scheduleInterval" value="60"></property> <!-- 拒绝策略: 当环已满, 无法继续填充时 --> <!-- 默认无需指定, 将丢弃Put操作, 仅日志记录. 如有特殊需求, 请实现RejectedPutBufferHandler接口(支持Lambda表达式) --> <property name="rejectedPutBufferHandler" ref="XxxxYourPutRejectPolicy"></property> <!-- 拒绝策略: 当环已空, 无法继续获取时 --> <!-- 默认无需指定, 将记录日志, 并抛出UidGenerateException异常. 如有特殊需求, 请实现RejectedTakeBufferHandler接口(支持Lambda表达式) --> <property name="rejectedTakeBufferHandler" ref="XxxxYourTakeRejectPolicy"></property> </bean> <!-- 用完即弃的WorkerIdAssigner, 依赖DB操作 --> <bean id="disposableWorkerIdAssigner" class="com.baidu.fsg.uid.worker.DisposableWorkerIdAssigner" />
Mybatis配置,mybatis-spring.xml配置说明如下:
<!-- Spring annotation扫描 --> <context:component-scan base-package="com.baidu.fsg.uid" /> <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> <property name="dataSource" ref="dataSource" /> <property name="mapperLocations" value="classpath:/META-INF/mybatis/mapper/M_WORKER*.xml" /> </bean> <!-- 事务相关配置 --> <tx:annotation-driven transaction-manager="transactionManager" order="1" /> <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name="dataSource" ref="dataSource" /> </bean> <!-- Mybatis Mapper扫描 --> <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"> <property name="annotationClass" value="org.springframework.stereotype.Repository" /> <property name="basePackage" value="com.baidu.fsg.uid.worker.dao" /> <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory" /> </bean> <!-- 数据源配置 --> <bean id="dataSource" parent="abstractDataSource"> <property name="driverClassName" value="${mysql.driver}" /> <property name="maxActive" value="${jdbc.maxActive}" /> <property name="url" value="${jdbc.url}" /> <property name="username" value="${jdbc.username}" /> <property name="password" value="${jdbc.password}" /> </bean> <bean id="abstractDataSource" class="com.alibaba.druid.pool.DruidDataSource" destroy-method="close"> <property name="filters" value="${datasource.filters}" /> <property name="defaultAutoCommit" value="${datasource.defaultAutoCommit}" /> <property name="initialSize" value="${datasource.initialSize}" /> <property name="minIdle" value="${datasource.minIdle}" /> <property name="maxWait" value="${datasource.maxWait}" /> <property name="testWhileIdle" value="${datasource.testWhileIdle}" /> <property name="testOnBorrow" value="${datasource.testOnBorrow}" /> <property name="testOnReturn" value="${datasource.testOnReturn}" /> <property name="validationQuery" value="${datasource.validationQuery}" /> <property name="timeBetweenEvictionRunsMillis" value="${datasource.timeBetweenEvictionRunsMillis}" /> <property name="minEvictableIdleTimeMillis" value="${datasource.minEvictableIdleTimeMillis}" /> <property name="logAbandoned" value="${datasource.logAbandoned}" /> <property name="removeAbandoned" value="${datasource.removeAbandoned}" /> <property name="removeAbandonedTimeout" value="${datasource.removeAbandonedTimeout}" /> </bean> <bean id="batchSqlSession" class="org.mybatis.spring.SqlSessionTemplate"> <constructor-arg index="0" ref="sqlSessionFactory" /> <constructor-arg index="1" value="BATCH" /> </bean>
0x05:测试
@Resource private UidGenerator uidGenerator; @Test public void testSerialGenerate() { // Generate UID long uid = uidGenerator.getUID(); // Parse UID into [Timestamp, WorkerId, Sequence] // {"UID":"180363646902239241","parsed":{ "timestamp":"2017-01-19 12:15:46", "workerId":"4", "sequence":"9" }} System.out.println(uidGenerator.parseUID(uid)); } |