五分钟整合springboot+mybatis-plus+druid+dynamic-datasource多数据源

版本

springboot 2.7.16
druid 1.1.22
mybatis-plus-boot-starter 3.4.2
mysql 5.7.38
dynamic-datasource-spring-boot-starter 4.1.3

当然别的版本应该也差不多，最多改改相关类

步骤

1、搭建一个简单springboot2.7.16+druid+mybatis-plus环境

五分钟搭建springboot2.7.16+druid+mybatis-plus环境

2、引入相关依赖

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--数据库配置-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.25</version>
        </dependency>
        <!--数据源-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.22</version>
        </dependency>
        <!--自动化配置-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.22</version>
        </dependency>
        <!--mybatis-plus -->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.4.2</version>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
            <version>4.1.3</version>
        </dependency>

3、配置文件引入数据源

spring:
  autoconfigure:
    #自动化配置 例外处理
    exclude: com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceAutoConfigure
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    dynamic:
      primary: master #设置默认的数据源或者数据源组,默认值即为mysql1
      strict: false #严格匹配数据源,默认false. true未匹配到指定数据源时抛异常,false使用默认数据源
      datasource:
        master:
          url: jdbc:mysql://localhost:3306/demo?serverTimezone=Asia/Shanghai
          username: root
          password: 123456
          driver-class-name: com.mysql.cj.jdbc.Driver # 3.2.0开始支持SPI可省略此配置
        slave1:
          url: jdbc:mysql://localhost:3306/demo2?serverTimezone=Asia/Shanghai
          username: root
          password: 123456
          driver-class-name: com.mysql.cj.jdbc.Driver

4、建库建表插入数据

#demo1
CREATE DATABASE demo1;
CREATE TABLE user(
     userid BIGINT  not null primary key COMMENT '主键ID,雪花算法生成',
    username VARCHAR(64) COMMENT '用户名称：这里用微信的昵称'
);
INSERT INTO `demo1`.`user` (`userid`, `username`) VALUES (1, '小林');
INSERT INTO `demo1`.`user` (`userid`, `username`) VALUES (2, '小马');
#demo2
CREATE DATABASE demo2;
CREATE TABLE user(
     userid BIGINT  not null primary key COMMENT '主键ID,雪花算法生成',
    username VARCHAR(64) COMMENT '用户名称：这里用微信的昵称'
);
INSERT INTO `demo2`.`user` (`userid`, `username`) VALUES (1, '小林2');
INSERT INTO `demo2`.`user` (`userid`, `username`) VALUES (2, '小马2');

5、新建User.class

package com.example.demo;
public class User {
    private String userid;
    private String username;
    public String getUserid() {
        return userid;
    }
    public void setUserid(String userid) {
        this.userid = userid;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    @Override
    public String toString() {
        return "User{" +
                "userid='" + userid + '\'' +
                ", username='" + username + '\'' +
                '}';
    }
}

6、在mapper，service或者方法上加上注解即可

MasterUserMapper.class

package com.example.demo.mapper.master;
import com.baomidou.dynamic.datasource.annotation.DS;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.example.demo.User;
import org.springframework.stereotype.Repository;
@Repository
@DS("master")
public interface MasterUserMapper extends BaseMapper<User> {
}

Slave1UserMapper.class

package com.example.demo.mapper.slave1;
import com.baomidou.dynamic.datasource.annotation.DS;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.example.demo.User;
import org.springframework.stereotype.Repository;
@Repository
@DS("slave1")
public interface Slave1UserMapper extends BaseMapper<User> {
}

7、在DemoController加上测试逻辑

package com.example.demo;
import com.example.demo.mapper.master.MasterUserMapper;
import com.example.demo.mapper.slave1.Slave1UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
@RestController
public class DemoController {
    @Autowired()
    MasterUserMapper masterUserMapper;
    @Autowired()
    Slave1UserMapper slave1UserMapper;
    @GetMapping("/find1")
    public List<User> find1(){
        return masterUserMapper.selectList(null);
    }
    @GetMapping("/find2")
    public List<User> find2(){
        return slave1UserMapper.selectList(null);
    }
}

8、启动类加上注解@MapperScan

package com.example.demo;
import com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceAutoConfigure;
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);
    }
}

9、启动访问

http://localhost:8080/find1

[
    {
        "userid": "1",
        "username": "小林1"
    },
    {
        "userid": "2",
        "username": "小马1"
    }
]

http://localhost:8080/find2

[
    {
        "userid": "1",
        "username": "小林2"
    },
    {
        "userid": "2",
        "username": "小马2"
    }
]

搞定,还是很简单的！

10、注意事项

p- rimary: master配置后，全局默认master主数据源，只要没有@DS注解显式申明切换数据源，默认就是master主数据源。
在同一个事务中，数据源不能切换。
@DS 可以注解在方法上和类上，同时存在方法注解优先于类上注解。
官方强烈建议只在service的类和方法上添加注解，不建议在mapper上添加注解。（我觉得还是得看具体需求）