Spring Boot项目中结合MyBatis实现MySQL的自动主从切换功能

<dependencies>
    <!-- Spring Boot Starter -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <!-- MyBatis Starter -->
    <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>2.2.0</version>
    </dependency>
    <!-- ShardingSphere for read-write splitting -->
    <dependency>
        <groupId>org.apache.shardingsphere</groupId>
        <artifactId>sharding-jdbc-spring-boot-starter</artifactId>
        <version>4.1.1</version>
    </dependency>
</dependencies>

spring:
  shardingsphere:
    datasource:
      names: master,slave0,slave1
      master:
        type: com.zaxxer.hikari.HikariDataSource
        driver-class-name: com.mysql.cj.jdbc.Driver
        jdbc-url: jdbc:mysql://master_host:3306/your_db?useSSL=false&serverTimezone=UTC
        username: your_username
        password: your_password
      slave0:
        type: com.zaxxer.hikari.HikariDataSource
        driver-class-name: com.mysql.cj.jdbc.Driver
        jdbc-url: jdbc:mysql://slave0_host:3306/your_db?useSSL=false&serverTimezone=UTC
        username: your_username
        password: your_password
      slave1:
        type: com.zaxxer.hikari.HikariDataSource
        driver-class-name: com.mysql.cj.jdbc.Driver
        jdbc-url: jdbc:mysql://slave1_host:3306/your_db?useSSL=false&serverTimezone=UTC
        username: your_username
        password: your_password
    masterslave:
      load-balance-algorithm-type: round_robin # 负载均衡策略
      name: ms_ds # 数据源名称
      master-data-source-name: master # 主库数据源名称
      slave-data-source-names: slave0,slave1 # 从库数据源名称列表
    props:
      sql:
        show: true # 是否显示SQL语句

package com.example.demo.mapper;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;
import java.util.List;
import java.util.Map;
@Mapper
public interface UserMapper {
    /**
     * 查询所有用户信息.
     * 注意：对于查询操作，ShardingSphere会选择其中一个从库来执行查询。
     *
     * @return 用户信息列表
     */
    @Select("SELECT * FROM users")
    List<Map<String, Object>> findAllUsers();
    /**
     * 更新用户信息.
     * 注意：写操作只会针对主库执行。
     *
     * @param id 用户ID
     * @param newName 新用户名
     */
    void updateUserById(@Param("id") Long id, @Param("newName") String newName);
}

package com.example.demo;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
@MapperScan("com.example.demo.mapper")
public class DemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

package com.example.demo.service;
import com.example.demo.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
import java.util.Map;
@Service
public class UserService {
    @Autowired
    private UserMapper userMapper;
    /**
     * 获取所有用户信息.
     *
     * @return 用户信息列表
     */
    public List<Map<String, Object>> getAllUsers() {
        return userMapper.findAllUsers();
    }
    /**
     * 更新用户名称.
     *
     * @param id       用户ID
     * @param newName 新用户名
     */
    public void updateUserName(Long id, String newName) {
        userMapper.updateUserById(id, newName);
    }
}