@Query, 값, DTO 조회하기

 

1. 단순 값 조회

public interface MemberRepository extends JpaRepository<Member, Long> {

    // @Query, 값, DTO 조회하기
    @Query("select m.username from Member m")
    List<String> findUsernameList();
}

 

단순 값 조회 테스트

    @Autowired MemberRepository memberRepository;

// 단순 값 조회
    @Test
    public void findUsernameList(){
        Member m1 = new Member("memberA", 10);
        Member m2 = new Member("member2", 20);
        memberRepository.save(m1);
        memberRepository.save(m2);

        List<String> usernameList = memberRepository.findUsernameList();
        for (String s : usernameList) {
            System.out.println("s = " + s);
        }
    }

 

 

2. DTO 조회

public interface MemberRepository extends JpaRepository<Member, Long> {

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

 

dto 조회 테스트

    @Autowired MemberRepository memberRepository;
    @Autowired TeamRepository teamRepository;

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

        Member m1 = new Member("memberA", 10);
        m1.setTeam(team);
        memberRepository.save(m1);

        List<MemberDto> memberDto = memberRepository.findMemberDto();
        for (MemberDto dto : memberDto) {
            System.out.println("dto = " + dto);
        }
    }