简介
Mybatis-puls 多数据源的使用，采用的是官方提供的dynamic-datasource-spring-boot-starter包的 @DS 注解，具体可以参考官网：
https://gitee.com/baomidou/dynamic-datasource-spring-boot-starter
pom.xml文件引入如下依赖
主要引入dynamic-datasource-spring-boot-starter包
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <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>http://maven.apache.org</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") @Data public 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; @Mapper public 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") @Mapper public 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; @Service public 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; @Service public 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springboot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") @SpringBootApplication public 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; @SpringBootTest public class MybatisPlusTest { @Autowired StudentService studentService; @Autowired TeacherService teacherService; @Test public 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); } }
