[Spring][Spring data Jpa] join하여 dto로 가져오기

package stduy.datajpa.entity;

import lombok.*;

import javax.persistence.*;

@Entity
@Getter
@Setter
@NoArgsConstructor(access = AccessLevel.PROTECTED)
@ToString(of = {"id", "username", "age"})
@NamedQuery(
        name="Member.findByUsername",
        query="select m from Member m where m.username = :username"
)

public class Member {
    @Id
    @GeneratedValue
    @Column(name = "member_id")
    private Long id;
    private String username;
    private int age;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "team_id")
    private Team team;

    public Member(String name) {
        this.username = name;
    }

    public Member(String name, int age, Team team) {
        this.username = name;
        this.age = age;
        if (team != null) {
            changeTeam(team);
        }
    }

    public Member(String name, int age) {
        this.username = name;
        this.age = age;

    }

    public void changeTeam(Team team) {
        this.team = team;
        team.getMembers().add(this);
    }


}

package stduy.datajpa.entity;

import lombok.*;

import javax.persistence.*;
import java.util.ArrayList;
import java.util.List;

@Entity
@Getter
@Setter
@NoArgsConstructor(access = AccessLevel.PROTECTED)
@ToString(of = {"id", "name"})
public class Team {
    @Id
    @GeneratedValue
    @Column(name = "team_id")
    private Long id;
    private String name;
    @OneToMany(mappedBy = "team")
    private List<Member> members = new ArrayList<>();

    public Team(String name) {
        this.name = name;
    }
}

package stduy.datajpa.dto;

import lombok.Data;

@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;
    }
}

public interface MemberRepository extends JpaRepository<Member, Long> {

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

Member와 Team을 join하여 레코드값을 받아온 후

new MemberDto - > MemberDto를 생성한후 생성자 메소드에 레코드 값들을 넣어서

List<MebmerDto>로 반환한다.

 

테스트 코드

@SpringBootTest
@Transactional
@Rollback(value = false)
class MemberRepositoryTest {
    @Autowired
    MemberRepository memberRepository;
    @Autowired
    TeamRepository teamRepository;

    @Test
    public void findMemberDto() {
        Member m1 = new Member("AAA", 10);
        memberRepository.save(m1);

        Team team = new Team("TeamA");
        m1.setTeam(team);
        teamRepository.save(team);

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