pom.xml文件引入如下依赖
主要引入dynamic-datasource-spring-boot-starter包
<project xmlns="#34; xmlns:xsi="#34;xsi:schemaLocation=" #34;><modelVersion>4.0.0</modelVersion> <groupId>com.olive</groupId><artifactId>mybatis-plus-multip-datasource</artifactId><version>0.0.1-SNAPSHOT</version><packaging>jar</packaging> <name>mybatis-multip-datasource</name><url> <parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.5.14</version><relativePath /> <!-- lookup parent from repository --></parent> <properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><maven.compiler.source>8</maven.compiler.source><maven.compiler.target>8</maven.compiler.target></properties> <dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency> <dependency><groupId>mysql</groupId><artifactId>mysql-connector- Java </artifactId></dependency> <dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId></dependency><dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId></dependency> <dependency><groupId>com.baomidou</groupId><artifactId>dynamic-datasource-spring-boot-starter</artifactId><version>3.5.2</version></dependency><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.5.2</version></dependency></dependencies></project> 配置两个数据源
分别为第一个主数据源(primary)，第二数据源(slave_1)，具体配置如下：
# 基本配置server: port: 8080 # 数据库spring: datasource: dynamic: primary: master #设置默认的数据源或者数据源组,默认值即为master 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 ://127.0.0.1:3306/db01?characterEncoding=utf-8&allowMultiQueries=true&autoReconnect=true username: root password: root driver-class-name: com.mysql.cj.jdbc.Driver # 3.2.0开始支持SPI可省略此配置 slave_1: url: jdbc:mysql://127.0.0.1:3306/crm72?characterEncoding=utf-8&allowMultiQueries=true&autoReconnect=true username: root password: root driver-class-name: com.mysql.cj.jdbc.Driver mybatis-plus: mapper-locations: mapper/*.xml type-aliases-package: com.olive.entity configuration: map-underscore-to-camel-case: true log-impl: org. apache .ibatis.logging.stdout.StdOutImpl jackson: serialization: indent-output: true 创建学生与老师实体类
学生实体类
package com.olive.entity; import java .io.Serializable; import com.baomidou.mybatisplus. annotation .IdType;import com.baomidou.mybatisplus.annotation.TableField;import com.baomidou.mybatisplus.annotation.TableId;import com.baomidou.mybatisplus.annotation.TableName;import lombok.Data; @TableName("t_student")@Datapublic class StudentDO implements Serializable{ @TableId(value="id", type = IdType.AUTO) private Long id; @TableField("user_name") private String name; @TableField("sex") private int sex; @TableField("grade") private String grade;} 老师实体类
package com.olive.entity; import java.io.Serializable; import com.baomidou.mybatisplus.annotation.IdType;import com.baomidou.mybatisplus.annotation.TableField;import com.baomidou.mybatisplus.annotation.TableId;import com.baomidou.mybatisplus.annotation.TableName;import lombok.Data; @Data@TableName("t_teacher")public class TeacherDO implements Serializable { @TableId(value = "id", type = IdType.AUTO) private Long id; @TableField("user_name")private String name; @TableField("sex")private int sex; @TableField("office")private String office;} 数据库持久类
StudentMapper持久类
package com.olive.mapper; import com.baomidou.mybatisplus.core.mapper.BaseMapper;import com.olive.entity.StudentDO;import org.apache.ibatis.annotations.Mapper; @Mapperpublic interface StudentMapper extends BaseMapper<StudentDO> { } TeacherMapper持久类
package com.olive.mapper; import com.baomidou.dynamic.datasource.annotation.DS;import com.baomidou.mybatisplus.core.mapper.BaseMapper;import com.olive.entity.TeacherDO;import org.apache.ibatis.annotations.Mapper; @DS("slave_1")@Mapperpublic interface TeacherMapper extends BaseMapper<TeacherDO> { } 以上，两个持久类的实现都是继承BaseMapper基类，该类提供了基本的增删改查的方法；要注意的是，TeacherMapper 类使用了@DS(“slave_1”)指定了数据源；而StudentMapper没有指定，使用的是默认的数据源。
服务类的实现
先定义操作学生和老师的两个接口
StudentService接口
package com.olive.service; import com.baomidou.mybatisplus.extension.service.IService;import com.olive.entity.StudentDO; public interface StudentService extends IService<StudentDO> {} TeacherService接口
package com.olive.service; import com.baomidou.mybatisplus.extension.service.IService;import com.olive.entity.TeacherDO; public interface TeacherService extends IService<TeacherDO> {} 再定义接口的实现类
StudentServiceImpl类
package com.olive.service.impl; import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;import com.olive.entity.StudentDO;import com.olive.mapper.StudentMapper;import com.olive.service.StudentService;import org.springframework.stereotype.Service; @Servicepublic class StudentServiceImpl extends ServiceImpl<StudentMapper, StudentDO> implements StudentService {} TeacherServiceImpl类
package com.olive.service.impl; import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;import com.olive.entity.TeacherDO;import com.olive.mapper.TeacherMapper;import com.olive.service.TeacherService;import org.springframework.stereotype.Service; @Servicepublic class TeacherServiceImpl extends ServiceImpl<TeacherMapper, TeacherDO> implements TeacherService { } 观察接口定义和接口实现，套路非常标准。都是实现和继承Mybatis-Plus提供的标准接口和基类
创建 spring boot引导类
package com.olive; import org.mybatis.spring.annotation.MapperScan;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication; @MapperScan("com.olive.mapper")@SpringBootApplicationpublic class Application { public static void main(String[] args) { SpringApplication.run(Application.class); } } 测试
package com.olive; import com.olive.service.StudentService;import com.olive.service.TeacherService;import org. junit .jupiter.api.Test;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.test.context.SpringBootTest; import com.olive.entity.StudentDO;import com.olive.entity.TeacherDO; @SpringBootTestpublic class MybatisPlusTest { @AutowiredStudentService studentService; @AutowiredTeacherService teacherService; @Testpublic void userSave() {StudentDO studentDO = new StudentDO();studentDO.setName("BUG弄潮儿");studentDO.setSex(1);studentDO.setGrade("一年级");studentService.save(studentDO); TeacherDO teacherDO = new TeacherDO();teacherDO.setName("Java乐园");teacherDO.setSex(2);teacherDO.setOffice("语文");teacherService.save(teacherDO);}} 
