MyBatis ネストしたオブジェクト マッピング 自分用メモ

ネストしたオブジェクトのマッピング

１対多の関係のマッピング

@Data
public class Student {

	private String studentId;
	
	private String roomId;
	
	private String name;
	
	private String age;
}

@Data
public class Teacher {

	private String teacherId;
	
	private String roomId;
	
	private String name;
	
	private String age;
	
	private String subject;
}

@Data
public class ClassRoomDto {

	private String teacherId;
	
	private String roomId;
	
	private Teacher teacher;
	
	private List<Student> studentList;
}

マッパー

@Mapper
public interface PracticeDao {

    List<ClassRoomDto> selectClassRoomList(@Param("teacherId") String teacherId);
    
}

xml

	<resultMap id="BaseMap" type="com.example.practice.dto.ClassRoomDto">
	    <id column="TEACHER_ID" jdbcType="CHAR" property="teacherId" />
	    <id column="ROOM_ID" jdbcType="CHAR" property="roomId" />
	    <association property="teacher" javaType="com.example.practice.entity.Teacher">
	        <id column="TEACHER_ID" jdbcType="CHAR" property="teacherId" />
	        <id column="ROOM_ID" jdbcType="CHAR" property="roomId" />
	        <result column="NAME" jdbcType="CHAR" property="name" />
	        <result column="AGE" jdbcType="CHAR" property="age" />
	        <result column="SUBJECT" jdbcType="CHAR" property="subject" />
	    </association>
	    <collection property="studentList" ofType="com.example.practice.entity.Student">
	        <id column="STUDENT_ID" jdbcType="CHAR" property="studentId" />
	        <id column="ROOM_ID" jdbcType="CHAR" property="roomId" />
	        <result column="S_NAME" jdbcType="CHAR" property="name" />
	        <result column="S_AGE" jdbcType="CHAR" property="age"/>
	    </collection>
	</resultMap>
	
	<select id="selectClassRoomList" parameterType="map" resultMap="BaseMap">
	    SELECT
	        T.TEACHER_ID
	        , T.ROOM_ID
	        , T.NAME
	        , T.AGE
	        , T.SUBJECT
	        , S.STUDENT_ID
	        , S.ROOM_ID
	        , S.NAME AS S_NAME
	        , S.AGE AS S_AGE
	    FROM
	        TEACHER T
	    INNER JOIN
	        STUDENT S
	        ON T.ROOM_ID = S.ROOM_ID
	    WHERE
	        T.TEACHER_ID = #{teacherId, jdbcType=CHAR}
	</select>

結果

[ClassRoomDto(teacherId=T001, roomId=A01, 
teacher=Teacher(teacherId=T001, roomId=A01, name=田中 一郎, age=40, subject=数学), 
studentList=[
  Student(studentId=S001, roomId=A01, name=山田 太郎, age=15), 
  Student(studentId=S004, roomId=A01, name=佐藤 次郎, age=15), 
  Student(studentId=S005, roomId=A01, name=高橋 花子, age=14)])]