1.ShardingSphere概述:
ShardingSphere是一套开源的分布式数据库中间件解决方案组成的生态圈,它由Sharding-JDBC、Sharding-Proxy和Sharding-Sidecar(计划中)这3款相互独立的产品组成,我们只关注 Sharding-JDBC即可 详情可见官网(地址:功能 :: ShardingSphere)
项目中主要用到Sharding-JDBC ,Sharding-JDBC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框架的使用
1.1 适用于任何基于Java的ORM框架,如:JPA, Hibernate, Mybatis, Spring JDBC Template或直接使用JDBC。
1.2 基于任何第三方的数据库连接池,如:DBCP, C3P0, Druid等。
1.3 支持任意实现JDBC规范的数据库。目前支持MySQL,Oracle,SQLServer和PostgreSQL
1.4 Sharding-JDBC主要实现数据分片和读写分离,通过Sharding-JDBC,应用可以透明的使用jdbc访问已经分库分表,读写分离的多个数据源,而不用关心数据源的数量以及数据如何分布
2.搭建ShardingSphere项目:
2.1 项目结果如下:
2.2 引入相关的pom依赖,本项目主要集成mybatis-plus 引入的依赖如下:
4.0.0 org.springframework.boot spring-boot-starter-parent 2.7.1 com.shardingsphere demo 0.0.1-SNAPSHOT shardingsphere Demo project for Spring Boot 1.8 org.springframework.boot spring-boot-starter-web mysql mysql-connector-java com.alibaba druid 1.2.6 com.baomidou mybatis-plus-boot-starter 3.4.0 org.apache.shardingsphere sharding-jdbc-spring-boot-starter 4.1.1 org.apache.shardingsphere sharding-transaction-xa-core 4.1.1 org.projectlombok lombok true org.springframework.boot spring-boot-starter-test test cn.hutool hutool-all 5.5.8 org.springframework.boot spring-boot-maven-plugin
2.3 创建测试的数据库表user 分别创建两个测试库ds-0 ds-1 然后分别在ds-0 ds-1库中创建数据库表user 创建脚本如下:
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
`id` bigint(32) NOT NULL,
`name` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,
`age` int(5) NULL DEFAULT NULL,
`sex` char(1) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL,
`education` char(1) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,
`creation_time` datetime NULL DEFAULT NULL ON UPDATE CURRENT_TIMESTAMP,
`update_time` datetime NULL DEFAULT NULL ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = DYNAMIC;
2.4 规则配置 主要通过sharding-jdbc对分库分表的规则进行配置,配置内容包括:数据源、主键生成策略、分片策略等 application.yml配置文件如下:
spring: shardingsphere: datasource: names: ds-0,ds-1 ds_0: url: jdbc:mysql://127.0.0.1:3306/ds-0?useUnicode=true&characterEncoding=UTF-8&serverTimezone=GMT%2B8&useSSL=false&useInformationSchema=false driver-class-name: com.mysql.cj.jdbc.Driver type: com.alibaba.druid.pool.DruidDataSource username: root password: hzp123456 ds_1: url: jdbc:mysql://127.0.0.1:3306/ds-1?useUnicode=true&characterEncoding=UTF-8&serverTimezone=GMT%2B8&useSSL=false&useInformationSchema=false driver-class-name: com.mysql.cj.jdbc.Driver type: com.alibaba.druid.pool.DruidDataSource username: root password: hzp123456 sharding: tables: user: actual-data-nodes: ds-$->{0..1}.user database-strategy: standard: sharding-column: age precise-algorithm-class-name: com.shardingsphere.algorithm.DefaultModuloPreciseShardingAlgorithm key-generator: column: id type: SNOWFLAKE props: worker.id: 11 executor.size: 4 max.connections.size.per.query: 1 check.table.metadata.enabled: false props: sql.show: true
以上配置解释说明:
配置数据节点,指定节点的信息:actual-data-nodes: ds-$->{0..1}.user $ 会被 大括号中的 {0…1} 所替换 生成对应的结果为ds-0.user和ds-1.user
分库策略:
sharding-column: age
precise-algorithm-class-name: com.shardingsphere.algorithm.DefaultModuloPreciseShardingAlgorithm
主要通过数据库中表user的age实现表的分库 具体可根据自己项目实际业务逻辑实现 以上配置通过类DefaultModuloPreciseShardingAlgorithm实现 DefaultModuloPreciseShardingAlgorithm类为:
package com.shardingsphere.algorithm; import org.apache.shardingsphere.api.sharding.standard.PreciseShardingAlgorithm; import org.apache.shardingsphere.api.sharding.standard.PreciseShardingValue; import java.util.Collection; public class DefaultModuloPreciseShardingAlgorithm implements PreciseShardingAlgorithm{ @Override public String doSharding(Collection availableTargetNames, PreciseShardingValue shardingValue) { String modulo = String.valueOf(shardingValue.getValue() % availableTargetNames.size()); for (String targetName : availableTargetNames) { if (targetName.endsWith(modulo)) return targetName; } throw new UnsupportedOperationException(); } }
由以上可看出当age为偶数时向ds-0库中的user表插入数据 当age为奇数时 向ds-1库中的user表插入数据 具体结果如下 ds-0库:
ds-1库:
2.5 测试user实现分库 首先创建下user实体类:
package com.shardingsphere.entity; import com.baomidou.mybatisplus.annotation.IdType; import com.baomidou.mybatisplus.annotation.TableId; import com.fasterxml.jackson.annotation.JsonFormat; import lombok.Data; import java.io.Serializable; import java.util.Date; /** * @Author 何志鹏 * @Date 2022/7/15 15:02 * @Version 1.0 */ @Data public class User implements Serializable { private static final long serialVersionUID = -94704944729049233L; @TableId(type = IdType.ASSIGN_ID) private Long id; private String name; private Long age; private String sex; private String education; @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss",timezone="GMT+8") private Date creationTime; @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss",timezone="GMT+8") private Date updateTime; }
2.6 创建一个UserMapper接口 继承mybatisplus中的BaseMapper 如下:
package com.shardingsphere.Mapper; import com.baomidou.mybatisplus.core.mapper.BaseMapper; import com.shardingsphere.entity.User; import org.apache.ibatis.annotations.Mapper; import org.springframework.stereotype.Repository; /** * @Author 何志鹏 * @Date 2022/7/15 15:10 * @Version 1.0 */ @Mapper @Repository public interface UserMapper extends BaseMapper{ }
2.7 写一个测试类DemoTest 向user表中写入数据 测下分库的结果 并且进行查询操作 代码如下:
package com.shardingsphere; import cn.hutool.core.util.IdUtil; import cn.hutool.json.JSONObject; import cn.hutool.json.JSONUtil; import com.shardingsphere.Mapper.UserMapper; import com.shardingsphere.entity.User; import org.junit.jupiter.api.Test; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.context.SpringBootTest; import java.util.Date; /** * @Author 何志鹏 * @Date 2022/7/15 15:15 * @Version 1.0 */ @SpringBootTest public class DemoTest { @Autowired private UserMapper userMapper; @Test void contextLoads() { User user = new User(); user.setName("何志鹏"); int randomNum = (int) (Math.random()*9000+1000); user.setAge(new Long(randomNum)); user.setSex("1"); user.setEducation("1"); user.setCreationTime(new Date()); user.setUpdateTime(new Date()); userMapper.insert(user); //ds-0库 User user0 = userMapper.selectById("1547874667537178626"); System.err.println("ds-0库:"+JSONUtil.parseObj(user0)); //ds-1库 User user1 = userMapper.selectById("1547874960127582210"); System.err.println("ds-1库:"+JSONUtil.parseObj(user1)); } }
最后附上代码: https://gitee.com/hezhipeng_ek/shardingsphere.git