SpringBoot+MyBatis+MySQL多数据源搭建

平时可能有需求需要一个项目中访问多个数据源。以下是搭建多数据源的一个简单方案。

一、案例环境

SpringBoot、MyBatis、MySQL；
下面是两个数据库school与school2，两个数据库中分别都有一个teacher表，但是数据不同，我们就来操作这两个数据库。如下

二、SpringBoot项目搭建

2.1 Maven依赖

都是最基础的，如果你要用到Generator生成lombox工程，你可以看上篇文章

		
	        org.springframework.boot
	        spring-boot-starter-web
	    
		
			org.mybatis.spring.boot
			mybatis-spring-boot-starter
			2.0.0
		
	     
	        mysql
	        mysql-connector-java
	    
		
			org.springframework.boot
			spring-boot-starter-test
			test
		
	
	
	
		
			
				org.springframework.boot
				spring-boot-maven-plugin
			
		
	

2.2 配置文件

我这里是application.yml格式，其它properties都是一样的。先展示一下我的文档结构，其中练习较杂，只看标注的即可。

下面是数据库配置，密码和账户非真，虚拟的。

server:
  port: 8080

spring:
  datasource:
    test1:
      driver-class-name: com.mysql.jdbc.Driver
      jdbc-url: jdbc:mysql://47.113.122.168:3306/school?useUnicode=true&characterEncoding=utf8&autoReconnect=true&serverTimezone=UTC
      username: root
      password: guaidonggua..
    test2:
      driver-class-name: com.mysql.jdbc.Driver
      jdbc-url: jdbc:mysql://47.113.122.168:3306/school2?useUnicode=true&characterEncoding=utf8&autoReconnect=true&serverTimezone=UTC
      username: root
      password: guaidonggua..

2.3 构建Mapper

我这里直接使用Generator生成两次，分别是两个数据库的Mapper类和配置文件。


下面象征性地展示数据源1的代码。

```yaml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.aiahtb.mapper.data1.Teacher1Mapper">
  <resultMap id="BaseResultMap" type="com.aiahtb.entity.Teacher">
    <id column="tid" jdbcType="INTEGER" property="tid" />
    <result column="name" jdbcType="VARCHAR" property="name" />
    <result column="age" jdbcType="INTEGER" property="age" />
    <result column="creat_time" jdbcType="TIMESTAMP" property="creatTime" />
    <result column="update_time" jdbcType="TIMESTAMP" property="updateTime" />
  </resultMap>
  <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer">
    delete from teacher
    where tid = #{tid,jdbcType=INTEGER}
  </delete>
  <insert id="insert" parameterType="com.aiahtb.entity.Teacher">
    insert into teacher (tid, `name`, age, 
      creat_time, update_time)
    values (#{tid,jdbcType=INTEGER}, #{name,jdbcType=VARCHAR}, #{age,jdbcType=INTEGER}, 
      #{creatTime,jdbcType=TIMESTAMP}, #{updateTime,jdbcType=TIMESTAMP})
  </insert>
  <update id="updateByPrimaryKey" parameterType="com.aiahtb.entity.Teacher">
    update teacher
    set `name` = #{name,jdbcType=VARCHAR},
      age = #{age,jdbcType=INTEGER},
      creat_time = #{creatTime,jdbcType=TIMESTAMP},
      update_time = #{updateTime,jdbcType=TIMESTAMP}
    where tid = #{tid,jdbcType=INTEGER}
  </update>
  <select id="selectByPrimaryKey" parameterType="java.lang.Integer" resultMap="BaseResultMap">
    select tid, `name`, age, creat_time, update_time
    from teacher
    where tid = #{tid,jdbcType=INTEGER}
  </select>
  <select id="selectAll" resultMap="BaseResultMap">
    select tid, `name`, age, creat_time, update_time
    from teacher
  </select>
</mapper>

public interface Teacher1Mapper {
    int deleteByPrimaryKey(Integer tid);

    int insert(Teacher record);

    Teacher selectByPrimaryKey(Integer tid);

    List<Teacher> selectAll();

    int updateByPrimaryKey(Teacher record);
}

2.4 数据源配置（重点）

数据源1的配置，千万要注意，单词过长，仔细仔细再仔细。

package com.aiahtb.config.datasource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;

/**
 * @MapperScan：使用@MapperScan来扫描注册mybatis数据库接口类， basePackages：表明接口类所在的包
 * sqlSessionTemplateRef：表明接口类使用的SqlSessionTemplate
 * @Primary：在spring容器中，区别一个接口不同实现在属性注入时的先后顺序 详情：https://www.cnblogs.com/liaojie970/p/7885106.html
 */
@Configuration
// 配置mybatis的接口类放的地方，使用扫描，mapper类上就不用添加@Mapper注解了
@MapperScan(basePackages = "com.aiahtb.mapper.data1", sqlSessionTemplateRef = "test1SqlSessionTemplate")
public class DatasourceConfig1 {

    @Bean(name = "test1DataSource")
    @ConfigurationProperties(prefix = "spring.datasource.test1")
    @Primary
    public DataSource testDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "test1SqlSessionFactory")
    @Primary
    public SqlSessionFactory testSqlSessionFactory(@Qualifier("test1DataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mapper/data1/*.xml"));
        return bean.getObject();
    }

    @Bean(name = "test1TransactionManager")
    @Primary
    public DataSourceTransactionManager testTransactionManager(@Qualifier("test1DataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "test1SqlSessionTemplate")
    @Primary
    public SqlSessionTemplate testSqlSessionTemplate(@Qualifier("test1SqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

数据源2的配置，千万要注意，单词过长，仔细仔细再仔细。

@Configuration
// 配置mybatis的接口类放的地方
@MapperScan(basePackages = "com.aiahtb.mapper.data2", sqlSessionTemplateRef = "test2SqlSessionTemplate")
public class DatasourceConfig2 {

    @Bean(name = "test2DataSource")
    @ConfigurationProperties(prefix = "spring.datasource.test2")
    public DataSource testDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean(name = "test2SqlSessionFactory")
    public SqlSessionFactory testSqlSessionFactory(@Qualifier("test2DataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mapper/data2/*.xml"));
        return bean.getObject();
    }

    @Bean(name = "test2TransactionManager")
    public DataSourceTransactionManager testTransactionManager(@Qualifier("test2DataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "test2SqlSessionTemplate")
    public SqlSessionTemplate testSqlSessionTemplate(@Qualifier("test2SqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

测试

使用测试类来测试一下。

@RunWith(SpringRunner.class)
@SpringBootTest(classes = Application.class) // 指定引导类
public class DemoApplicationTests {
    private static final Logger logger = LoggerFactory.getLogger(DemoApplicationTests.class);

    @Autowired
    private Teacher1Mapper teacher1Mapper;
    @Autowired
    private Teacher2Mapper teacher2Mapper;

    /**
     * 测试多数据源
     */
    @Test
    public void moreDataSource() {
        System.out.println("测试多数据源\n");

        teacher1Mapper.selectAll().forEach(n -> {
            System.out.println(n.toString());
        });

        System.out.println("\n");

        teacher2Mapper.selectAll().forEach(n -> {
            System.out.println(n.toString());
        });

        System.out.println("\n");
    }
}

测试结果

[参考文献]
纯洁的微笑：http://www.ityouknow.com/springboot/2016/11/25/spring-boot-multi-mybatis.html