spring boot mybatis 多数据源

在Spring Boot中使用MyBatis实现多数据源的方式有很多种，下面介绍两种常用的方法。

方法一：使用Spring Boot的自动配置

1.在application.yml或application.properties中定义多个数据源的配置信息，如下所示：

# 数据源1
spring.datasource.master.jdbc-url=jdbc:mysql://localhost:3306/db_master
spring.datasource.master.username=root
spring.datasource.master.password=123456
spring.datasource.master.driver-class-name=com.mysql.jdbc.Driver

# 数据源2
spring.datasource.slave.jdbc-url=jdbc:mysql://localhost:3306/db_slave
spring.datasource.slave.username=root
spring.datasource.slave.password=123456
spring.datasource.slave.driver-class-name=com.mysql.jdbc.Driver

2.创建多个数据源的连接池和SqlSessionFactory，可以使用Spring Boot自动配置的方式来实现。只需要在配置类上添加@MapperScan注解即可，如下所示：

@Configuration
@MapperScan(basePackages = "com.example.mapper")
public class MybatisConfig {
    @Bean
    @ConfigurationProperties(prefix="spring.datasource.master")
    public DataSource masterDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean
    @ConfigurationProperties(prefix="spring.datasource.slave")
    public DataSource slaveDataSource() {
        return DataSourceBuilder.create().build();
    }

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

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

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

    @Bean(name = "slaveSqlSessionTemplate")
    public SqlSessionTemplate slaveSqlSessionTemplate(@Qualifier("slaveSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

3.在Mapper接口中使用@Qualifier注解来指定使用哪个数据源，如下所示：

public interface UserMapper {
    @Select("select * from user")
    @Qualifier("masterSqlSessionFactory")
    List<User> selectAllMaster();

    @Select("select * from user")
    @Qualifier("slaveSqlSessionFactory")
    List<User> selectAllSlave();
}

方法二：手动配置多个数据源

1.定义多个数据源的配置信息，如下所示：

@Configuration
public class DataSourceConfig {
    @Bean(name = "masterDataSource")
    @ConfigurationProperties(prefix="spring.datasource.master")
    public DataSource masterDataSource() {
        return DataSourceBuilder.create().build();
    }

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

2.创建多个SqlSessionFactory，如下所示：

@Configuration
public class MybatisConfig {
    @Autowired
    @Qualifier("masterDataSource")
    private DataSource masterDataSource;

    @Autowired
    @Qualifier("slaveDataSource")
    private DataSource slaveDataSource;

    @Bean(name = "masterSqlSessionFactory")
    public SqlSessionFactory masterSqlSessionFactory() throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(masterDataSource);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mapper/master/*.xml"));
        return bean.getObject();
    }

    @Bean(name = "slaveSqlSessionFactory")
    public SqlSessionFactory slaveSqlSessionFactory() throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(slaveDataSource);
        bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mapper/slave/*.xml"));
        return bean.getObject();
    }

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

    @Bean(name = "slaveSqlSessionTemplate")
    public SqlSessionTemplate slaveSqlSessionTemplate(@Qualifier("slaveSqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

3.在Mapper接口中使用@Qualifier注解来指定使用哪个数据源，如下所示：

public interface UserMapper {
    @Select("select * from user")
    @Qualifier("masterSqlSessionFactory")
    List<User> selectAllMaster();

    @Select("select * from user")
    @Qualifier("slaveSqlSessionFactory")
    List<User> selectAllSlave();
}

以上就是Spring Boot中使用MyBatis实现多数据源的两种常用方法，具体使用哪种方法，可以根据自己的实际情况来选择。