1、shardingjdbc介绍

1.1、读写分离、数据分片（分库分表）中间件：

1.1.1、shardingsphere

1. proxy：创建一个中间层项目，处理所有的数据库操作分发请求
2. jdbc：在一个项目的配置文件中配置读写分离

1.1.2、mycat

2、shardingjdbc-demo搭建

2.1、创建项目

项目类型：Spring Initializr
SpringBoot脚手架：https://start.springboot.io
项目名：sharding-jdbc-demo
SpringBoot版本：3.0.5

2.2、添加依赖

    <dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><!--操作数据库--><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.30</version></dependency><!--mybatisPlus--><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.5.3.1</version></dependency><!--lombok--><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><optional>true</optional></dependency><dependency><groupId>org.apache.shardingsphere</groupId><artifactId>shardingsphere-jdbc-core</artifactId><version>5.4.0</version></dependency><!--兼容jdk17和spring boot3--><dependency><groupId>org.yaml</groupId><artifactId>snakeyaml</artifactId><version>1.33</version></dependency><dependency><groupId>org.glassfish.jaxb</groupId><artifactId>jaxb-runtime</artifactId><version>2.3.8</version></dependency></dependencies>

2.3、application.yml

spring:datasource:driver-class-name: com.mysql.cj.jdbc.Driverusername: rootpassword: 123456url: jdbc:mysql://192.168.74.148:3306/mydb2?serverTimezone=GMT%2B8

2.4、创建实体类 User

create table t_user
(id   BIGINT auto_increment,name VARCHAR(30) null,constraint t_user_pkprimary key (id)
);

package com.atguigu.sharding.jdbc.demo.bean;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.Data;
@Data
@TableName(value = "t_user")
public class User {private Long id;private String name;}

2.5、创建 UserMapper

package com.atguigu.sharding.jdbc.demo.mapper;
import com.atguigu.sharding.jdbc.demo.bean.User;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import org.apache.ibatis.annotations.Mapper;
@Mapper
public interface UserMapper extends BaseMapper<User> {
}

2.6、创建测试类 ShardingJdbcDemoApplicationTests

package com.atguigu.sharding.jdbc.demo;import com.atguigu.sharding.jdbc.demo.mapper.UserMapper;
import jakarta.annotation.Resource;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;@SpringBootTest
class ShardingJdbcDemoApplicationTests {@ResourceUserMapper userMapper;@Testvoid contextLoads() {userMapper.selectList(null).forEach(System.out::println);}}

2024-09-23T21:17:04.983+08:00  INFO 3416 --- [           main] a.s.j.d.ShardingJdbcDemoApplicationTests : Started ShardingJdbcDemoApplicationTests in 2.135 seconds (process running for 3.649)
2024-09-23T21:17:05.518+08:00  INFO 3416 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Starting...
2024-09-23T21:17:06.147+08:00  INFO 3416 --- [           main] com.zaxxer.hikari.pool.HikariPool        : HikariPool-1 - Added connection com.mysql.cj.jdbc.ConnectionImpl@6a4a2090
2024-09-23T21:17:06.150+08:00  INFO 3416 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Start completed.
User(id=1, name=张三)
User(id=2, name=李四)
2024-09-23T21:17:06.250+08:00  INFO 3416 --- [ionShutdownHook] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown initiated...
2024-09-23T21:17:06.256+08:00  INFO 3416 --- [ionShutdownHook] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown completed.