一、Sharding-jdbc简介Sharding-jdbc是开源的数据库操作中间件；定位为轻量级Java框架，在Java的JDBC层提供的额外服务。它使用客户端直连数据库，以jar包形式提供服务，无需额外部署和依赖，可理解为增强版的JDBC驱动，完全兼容JDBC和各种ORM框架。官方文档地址：https://shardingsphere.apache.org/document/current/cn/overview/本文demo实现了分库分表功能。作者能力有限，如有错误，欢迎各位在评论中指出。不胜感激！二、项目结构首先创建一个一般的Springboot项目，项目采用三层架构，结构图如下：项目目录结构图POM.xml文件如下：<?xmlversion="1.0"encoding="UTF-8"?><projectxmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.1.6.RELEASE</version><relativePath/><!--lookupparentfromrepository--></parent><groupId>com.macky</groupId><artifactId>spring-boot-shardingjdbc</artifactId><version>0.0.1-SNAPSHOT</version><name>spring-boot-shardingjdbc</name><description>Demoprojectforspring-boot-shardingjdbc</description><properties><java.version>1.8</java.version></properties><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><!--mysql--><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><scope>runtime</scope></dependency><!--Mybatis-Plus--><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.1.1</version></dependency><!--shardingspherestart--><!--forspringboot--><dependency><groupId>io.shardingsphere</groupId><artifactId>sharding-jdbc-spring-boot-starter</artifactId><version>3.1.0</version></dependency><!--forspringnamespace--><dependency><groupId>io.shardingsphere</groupId><artifactId>sharding-jdbc-spring-namespace</artifactId><version>3.1.0</version></dependency><!--shardingsphereend--><!--lombok--><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build></project>实体类以书本为例packagecom.macky.springbootshardingjdbc.entity;importcom.baomidou.mybatisplus.annotation.TableName;importcom.baomidou.mybatisplus.extension.activerecord.Model;importgroovy.transform.EqualsAndHashCode;importlombok.Data;importlombok.experimental.Accessors;/***@authorMacky*@TitleclassBook*@Description:书籍是实体类*@date2019/7/1315:23*/@Data@EqualsAndHashCode(callSuper=true)@Accessors(chain=true)@TableName("book")publicclassBookextendsModel<Book>{privateintid;privateStringname;privateintcount;}开放保存和查询两个接口，代码如下：packagecom.macky.springbootshardingjdbc.controller;importcom.macky.springbootshardingjdbc.entity.Book;importcom.macky.springbootshardingjdbc.service.BookService;importorg.springframework.beans.factory.annotation.Autowired;importorg.springframework.web.bind.annotation.*;importjava.util.List;/***@authorMacky*@TitleclassBookController*@Description:TODO*@date2019/7/1220:53*/@RestControllerpublicclassBookController{@AutowiredBookServicebookService;@RequestMapping(value="/book",method=RequestMethod.GET)publicList<Book>getItems(){returnbookService.getBookList();}@RequestMapping(value="/book",method=RequestMethod.POST)publicBooleansaveItem(Bookbook){returnbookService.save(book);}}BookServiceImpl.javapackagecom.macky.springbootshardingjdbc.service.impl;importcom.baomidou.mybatisplus.core.toolkit.Wrappers;importcom.baomidou.mybatisplus.extension.service.impl.ServiceImpl;importcom.macky.springbootshardingjdbc.entity.Book;importcom.macky.springbootshardingjdbc.mapper.BookMapper;importcom.macky.springbootshardingjdbc.service.BookService;importorg.springframework.stereotype.Service;importjava.util.List;/***@authorMacky*@TitleclassBookServiceImpl*@Description:TODO*@date2019/7/1220:47*/@ServicepublicclassBookServiceImplextendsServiceImpl<BookMapper,Book>implementsBookService{@OverridepublicList<Book>getBookList(){returnbaseMapper.selectList(Wrappers.<Book>lambdaQuery());}@Overridepublicbooleansave(Bookbook){returnsuper.save(book);}}BookMapper.javapackagecom.macky.springbootshardingjdbc.mapper;importcom.baomidou.mybatisplus.core.mapper.BaseMapper;importcom.macky.springbootshardingjdbc.entity.Book;/***@authorMacky*@TitleclassBookMapper*@Description:TODO*@date2019/7/1220:46*/publicinterfaceBookMapperextendsBaseMapper<Book>{}创建数据库表，DDL语句如下:#创建数据库表数据CREATEDATABASEIFNOTEXISTS`db0`;USE`db0`;DROPTABLEIFEXISTS`book_0`;CREATETABLE`book_0`(`id`INT(11)NOTNULL,`name`VARCHAR(255)DEFAULTNULL,`count`INT(11)DEFAULTNULL,PRIMARYKEY(`id`))ENGINE=INNODBDEFAULTCHARSET=utf8mb4;DROPTABLEIFEXISTS`book_1`;CREATETABLE`book_1`(`id`INT(11)NOTNULL,`name`VARCHAR(255)DEFAULTNULL,`count`INT(11)DEFAULTNULL,PRIMARYKEY(`id`))ENGINE=INNODBDEFAULTCHARSET=utf8mb4;CREATEDATABASEIFNOTEXISTS`db1`;USE`db1`;DROPTABLEIFEXISTS`book_0`;CREATETABLE`book_0`(`id`INT(11)NOTNULL,`name`VARCHAR(255)DEFAULTNULL,`count`INT(11)DEFAULTNULL,PRIMARYKEY(`id`))ENGINE=INNODBDEFAULTCHARSET=utf8mb4;DROPTABLEIFEXISTS`book_1`;CREATETABLE`book_1`(`id`INT(11)NOTNULL,`name`VARCHAR(255)DEFAULTNULL,`count`INT(11)DEFAULTNULL,PRIMARYKEY(`id`))ENGINE=INNODBDEFAULTCHARSET=utf8mb4;CREATEDATABASEIFNOTEXISTS`db2`;USE`db2`;DROPTABLEIFEXISTS`book_0`;CREATETABLE`book_0`(`id`INT(11)NOTNULL,`name`VARCHAR(255)DEFAULTNULL,`count`INT(11)DEFAULTNULL,PRIMARYKEY(`id`))ENGINE=INNODBDEFAULTCHARSET=utf8mb4;DROPTABLEIFEXISTS`book_1`;CREATETABLE`book_1`(`id`INT(11)NOTNULL,`name`VARCHAR(255)DEFAULTNULL,`count`INT(11)DEFAULTNULL,PRIMARYKEY(`id`))ENGINE=INNODBDEFAULTCHARSET=utf8mb4;配置分库分表策略application.properties：#数据源db0,db1,db2sharding.jdbc.datasource.names=db0,db1,db2#第一个数据库sharding.jdbc.datasource.db0.type=com.zaxxer.hikari.HikariDataSourcesharding.jdbc.datasource.db0.driver-class-name=com.mysql.cj.jdbc.Driversharding.jdbc.datasource.db0.jdbc-url=jdbc:mysql://localhost:3306/db0?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTCsharding.jdbc.datasource.db0.username=rootsharding.jdbc.datasource.db0.password=Aa123456#第二个数据库sharding.jdbc.datasource.db1.type=com.zaxxer.hikari.HikariDataSourcesharding.jdbc.datasource.db1.driver-class-name=com.mysql.cj.jdbc.Driversharding.jdbc.datasource.db1.jdbc-url=jdbc:mysql://localhost:3306/db1?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTCsharding.jdbc.datasource.db1.username=rootsharding.jdbc.datasource.db1.password=Aa123456#第三个数据库sharding.jdbc.datasource.db2.type=com.zaxxer.hikari.HikariDataSourcesharding.jdbc.datasource.db2.driver-class-name=com.mysql.cj.jdbc.Driversharding.jdbc.datasource.db2.jdbc-url=jdbc:mysql://localhost:3306/db2?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTCsharding.jdbc.datasource.db2.username=rootsharding.jdbc.datasource.db2.password=Aa123456#水平拆分的数据库（表）配置分库+分表策略行表达式分片策略#分库策略sharding.jdbc.config.sharding.default-database-strategy.inline.sharding-column=idsharding.jdbc.config.sharding.default-database-strategy.inline.algorithm-expression=db$->{id%3}#分表策略其中book为逻辑表分表主要取决于id行sharding.jdbc.config.sharding.tables.book.actual-data-nodes=db$->{0..2}.book_$->{0..2}sharding.jdbc.config.sharding.tables.book.table-strategy.inline.sharding-column=count#分片算法表达式sharding.jdbc.config.sharding.tables.book.table-strategy.inline.algorithm-expression=book_$->{count%3}#主键UUID18位数如果是分布式还要进行一个设置防止主键重复#sharding.jdbc.config.sharding.tables.user.key-generator-column-name=id#打印执行的数据库以及语句sharding.jdbc.config.props..sql.show=truespring.main.allow-bean-definition-overriding=true#读写分离sharding.jdbc.datasource.dsmaster=接口测试使用postman示例：GET请求------>http://localhost:8080/bookPOST请求：------->http://localhost:8080/book?id=1&name=java编程思想&count=8demo的github地址：https://github.com/Macky-He/spring-boot--shardingsphere-examples如各位觉得有帮助的话，还请给个star鼓励鼓励博主，谢谢！三、总结分库分表实现按照官方文档做一个demo是第一步，如需深入还需要研究源码，研究架构，研究思想；此文仅作为入门demo搭建指南，如需深入理解，还请移步至官方文档。参考资料1.官方文档：https://shardingsphere.apache.org/document/current/cn/manual/sharding-jdbc/usage/sharding/