mybatisplus如何指定使用druid多数据源

MybatisPlus可以通过配置多个数据源来实现对多个数据库的访问，同时也可以使用Druid作为数据源连接池。下面是一个使用Druid多数据源的MybatisPlus配置示例：

1. 引入Druid和MybatisPlus的依赖：

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>${druid.version}</version>
</dependency>

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>${mybatis-plus.version}</version>
</dependency>

2. 配置数据源连接池，并定义多个数据源：

@Configuration
public class DataSourceConfig {

    @Bean
    @ConfigurationProperties("spring.datasource.druid.master")
    public DruidDataSource masterDataSource() {
        return DruidDataSourceBuilder.create().build();
    }

    @Bean
    @ConfigurationProperties("spring.datasource.druid.slave")
    public DruidDataSource slaveDataSource() {
        return DruidDataSourceBuilder.create().build();
    }

    @Primary
    @Bean(name = "master")
    public DataSource master(@Qualifier("masterDataSource") DruidDataSource dataSource) {
        return dataSource;
    }

    @Bean(name = "slave")
    public DataSource slave(@Qualifier("slaveDataSource") DruidDataSource dataSource) {
        return dataSource;
    }
}

3. 配置MybatisPlus的SqlSessionFactory，指定要使用的数据源：

@Configuration
@MapperScan(basePackages = {"com.example.mapper"})
public class MybatisPlusConfig {

    @Autowired
    @Qualifier("master")
    private DataSource masterDataSource;

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

    @Bean
    public SqlSessionFactory masterSqlSessionFactory() throws Exception {
        MybatisSqlSessionFactoryBean factoryBean = new MybatisSqlSessionFactoryBean();
        factoryBean.setDataSource(masterDataSource);
        return factoryBean.getObject();
    }

    @Bean
    public SqlSessionFactory slaveSqlSessionFactory() throws Exception {
        MybatisSqlSessionFactoryBean factoryBean = new MybatisSqlSessionFactoryBean();
        factoryBean.setDataSource(slaveDataSource);
        return factoryBean.getObject();
    }

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

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

4. 在Mapper接口中使用`@Mapper`注解指定要使用的SqlSessionTemplate：

@Mapper
public interface UserMapper {

    @Select("select * from user where id = #{id}")
    User selectById(@Param("id") Long id);

}

@Mapper
public interface OrderMapper {

    @Select("select * from order where user_id = #{userId}")
    List<Order> selectByUserId(@Param("userId") Long userId);

}

@Service
public class UserService {

    @Autowired
    @Qualifier("masterSqlSessionTemplate")
    private SqlSessionTemplate masterSqlSessionTemplate;

    @Autowired
    @Qualifier("slaveSqlSessionTemplate")
    private SqlSessionTemplate slaveSqlSessionTemplate;

    @Autowired
    private UserMapper userMapper;

    public User selectUserById(Long id) {
        return userMapper.selectById(id);
    }

}

@Service
public class OrderService {

    @Autowired
    @Qualifier("slaveSqlSessionTemplate")
    private SqlSessionTemplate slaveSqlSessionTemplate;

    @Autowired
    private OrderMapper orderMapper;

    public List<Order> selectOrdersByUserId(Long userId) {
        return orderMapper.selectByUserId(userId);
    }

}

通过以上配置，就可以实现使用Druid连接池的MybatisPlus多数据源配置。