<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

    <properties>
        <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://127.0.0.1/test?useUnicode=true&amp;characterEncoding=utf-8&amp;useSSL=false&amp;serverTimezone=Asia/Shanghai&amp;allowPublicKeyRetrieval=true"/>
        <property name="username" value="root"/>
        <property name="password" value="123456"/>
    </properties>

    <settings>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
    </settings>

    <environments default="default">
        <environment id="default">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <mapper resource="mapper/MapKeyMapper.xml"/>
    </mappers>

</configuration>

<?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.ys.mybatis.mapper.MapKeyMapper">

    <select id="getBlogMapById" resultType="map">
         select id, title from blog where id = #{id}
    </select>

    <select id="listBlogMap" resultType="map">
         select id, title from blog
    </select>

</mapper>

public interface MapKeyMapper {

    Map<String, Object> getBlogMapById(Integer id);

    Map<String, Object> listBlogMap();
}

@Slf4j
public class MapKeyTest {

    private SqlSessionFactory sqlSessionFactory;

    @BeforeEach
    public void init() {
        InputStream inputStream = ConfigurationTest.class.getClassLoader().getResourceAsStream("mybatis-config.xml");
        sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
    }


    @Test
    public void singleRowTest() {

        SqlSession sqlSession = sqlSessionFactory.openSession();

        MapKeyMapper mapper = sqlSession.getMapper(MapKeyMapper.class);
        Map<String, Object> map = mapper.getBlogMapById(1);
        System.out.println(map);

    }

    @Test
    public void multiLineTest() {

        SqlSession sqlSession = sqlSessionFactory.openSession();

        MapKeyMapper mapper = sqlSession.getMapper(MapKeyMapper.class);
        Map<String, Object> map = mapper.listBlogMap();
        System.out.println(map);
    }


}

@MapKey("id")
Map<String, Object> getBlogMapById(Integer id);

@MapKey("id")
Map<String, Object> listBlogMap();

public class MapperMethod {

  private final SqlCommand command;
  private final MethodSignature method;

  public MapperMethod(Class<?> mapperInterface, Method method, Configuration config) {
    this.command = new SqlCommand(config, mapperInterface, method);
    this.method = new MethodSignature(config, mapperInterface, method);
  }
}