@Query, 값, DTO 조회하기

1. 등록된 회원들의 이름을 조회

---

• MemberRepository

@Query("select m.userName from Member m")
    List<String> findUserNameList();

• Test

 @Test
    public void findUserNameList(){
        Member member1 = new Member("aaa", 10);
        Member member2 = new Member("bbb", 20);
        memberRepository.save(member1);
        memberRepository.save(member2);

        List<String> userNameList = memberRepository.findUserNameList();
        for (String userName : userNameList) {
            System.out.println("userName = " + userName);
        }

    }

 

 

2. Dto로 조회

---

• MemberDto

@Data
public class MemberDto {

    private Long id;
    private String userName;
    private String teamName;

    public MemberDto(Long id, String userName, String teamName) {
        this.id = id;
        this.userName = userName;
        this.teamName = teamName;
    }
}

• MemberRepository
  • 쿼리내에서 new를 통해 Dto를 생성하여 반환.
  •  

@Query("select new study.datajpa.dto.MemberDto(m.id, m.userName, t.name) from Member m join m.team t")
List<MemberDto> findMemberDto();

• Test

    @Test
    public void findMemberDto(){
        Team team = new Team("teamA");
        teamRepository.save(team);

        Member member1 = new Member("aaa", 10);
        member1.changeTeam(team);
        memberRepository.save(member1);

        List<MemberDto> memberDtos = memberRepository.findMemberDto();

        System.out.println("========================");
        for (MemberDto memberDto : memberDtos) {
            System.out.println("memberDto = " + memberDto);
        }
    }

 

3.GitHub : 210829 @Query, Dto

---

 

GitHub - bsh6463/SpringDataJpa