SpringBoot2.0之八 多数据源配置

  在开发的过程中我们可能都会遇到对接公司其他系统等需求，对于外部的系统可以采用接口对接的方式，对于一个公司开发的两个系统，并且知道相关数据库结构的情况下，就可以考虑使用多数据源来解决这个问题。SpringBoot为我们提供了相对简单的实现。

一、建立如下结构的maven项目

二、添加相关数据库配置信息

server:
  port: 8080

spring:  
  datasource:
    master:
      driver-class-name: com.mysql.jdbc.Driver
      url: jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=utf-8&useSSL=false
      username: root
      password: 123456
    slaver:
      driver-class-name: com.mysql.jdbc.Driver
      url: jdbc:mysql://127.0.0.1:3306/dev?useUnicode=true&characterEncoding=utf-8&useSSL=false
      username: root
      password: 123456

三、主库和从库的相关配置
1、主库数据源配置

@Configuration
@MapperScan(basePackages = "com.somta.springboot.dao.master", sqlSessionTemplateRef  = "masterSqlSessionTemplate")
public class MasterDataSourceConfiguration {

    @Value("${spring.datasource.master.driver-class-name}")
    private String driverClassName;

    @Value("${spring.datasource.master.url}")
    private String url;

    @Value("${spring.datasource.master.username}")
    private String username;

    @Value("${spring.datasource.master.password}")
    private String password;

    @Bean(name = "masterDataSource")
    @Primary
    public DataSource dataSource() {
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(this.driverClassName);
        dataSource.setUrl(this.url);
        dataSource.setUsername(this.username);
        dataSource.setPassword(this.password);
        return dataSource;
    }

    @Bean(name = "masterSqlSessionFactory")
    @Primary
    public SqlSessionFactory sqlSessionFactory(@Qualifier("masterDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:mybatis/master/**/Mysql_*Mapper.xml"));
        return bean.getObject();
    }

    @Bean(name = "masterTransactionManager")
    @Primary
    public DataSourceTransactionManager transactionManager(@Qualifier("masterDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "masterSqlSessionTemplate")
    @Primary
    public SqlSessionTemplate sqlSessionTemplate(@Qualifier("masterSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }

}

2、从库的数据源配置信息

@Configuration
@MapperScan(basePackages = "com.somta.springboot.dao.slaver", sqlSessionTemplateRef  = "slaverSqlSessionTemplate")
public class SlaverDataSourceConfiguration {

    @Value("${spring.datasource.slaver.driver-class-name}")
    private String driverClassName;

    @Value("${spring.datasource.slaver.url}")
    private String url;

    @Value("${spring.datasource.slaver.username}")
    private String username;

    @Value("${spring.datasource.slaver.password}")
    private String password;


    @Bean(name = "slaverDataSource")
    public DataSource dataSource() {
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(this.driverClassName);
        dataSource.setUrl(this.url);
        dataSource.setUsername(this.username);
        dataSource.setPassword(this.password);
        return dataSource;
    }

    @Bean(name = "slaverSqlSessionFactory")
    public SqlSessionFactory sqlSessionFactory(@Qualifier("slaverDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:mybatis/slaver/**/Mysql_*Mapper.xml"));
        return bean.getObject();
    }

    @Bean(name = "slaverTransactionManager")
    public DataSourceTransactionManager transactionManager(@Qualifier("slaverDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean(name = "slaverSqlSessionTemplate")
    public SqlSessionTemplate sqlSessionTemplate(@Qualifier("slaverSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }

}

  注意在配置数据源的信息时，一定要通过@Primary配置一个主库，对于数据库配置部分与普通的数据源配置没有差异，新建一个DataSource，在创建一个SqlSessionTemplate，最后创建一个SqlSessionTemplate，分别以此注入即可，@MapperScan注解的扫描路径要分别对于相应的dao层

四、编写dao层和xml

public interface UserMasterDao {
    int addUser(User user);
    int deleteUserById(Long id);
    int updateUserById(User user);
    User queryUserById(Long id);
    List<User> queryUserList();
}

<?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.somta.springboot.dao.master.UserMasterDao" > 
<!-- Result Map-->
<resultMap id="BaseResultMap" type="com.somta.springboot.pojo.User" >
    <result column="id" property="id"/>
    <result column="name" property="name"/>
    <result column="age" property="age"/>
</resultMap>

<!-- th_role_user table all fields -->
<sql id="Base_Column_List" >
    id, name, age
</sql>

<insert id="addUser" parameterType="com.somta.springboot.pojo.User" >
    insert into t_user (id, name, age) 
    values (#{id},#{name},#{age});
</insert>

<delete id="deleteUserById" parameterType="java.lang.Long">
 delete from t_user where id=#{id}
</delete>

<update id="updateUserById" parameterType="com.somta.springboot.pojo.User" >
    update t_user set 
    <trim  suffixOverrides="," >
    <if test="id != null and id != ''">
        id=#{id},
    </if>
    <if test="name != null and name != ''">
        name=#{name},
    </if>
    <if test="age != null and age != ''">
        age=#{age},
    </if>
    </trim> where id=#{id}
</update>

<select id="queryUserById" resultMap="BaseResultMap" parameterType="java.lang.Long">
    select <include refid="Base_Column_List" /> 
    from t_user where id = #{id}
</select>

<select id="queryUserList" resultMap="BaseResultMap">
    select <include refid="Base_Column_List" /> 
    from t_user
</select>

</mapper>   

五、编写测试类进行测试

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = Application.class)
public class MultiDatasourceTest {
    @Autowired
    private UserMasterDao masterUserDao;
    @Autowired
    private UserSlaverDao slaverUserDao;
    /**
     * 查询用户
     * @throws Exception
     */
    @Test
    public void testQueryUser() throws Exception {
        User masterUser = masterUserDao.queryUserById(1L);
        System.out.println("masterUser==>"+masterUser.getName());

        User slaverUser = slaverUserDao.queryUserById(1L);
        System.out.println("slaverUser==>"+slaverUser.getName());
    }
}

当在控制台看到如下所示输出就代表我们的配置已经成功了

Git代码地址：https://gitee.com/songhu/SpringBoot/tree/master/SpringBoot-multiDatasource

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