동적 쿼리와 성능 최적화 조회 - Builder 사용

MemberTeamDto - 조회 최적화용 DTO 추가

@Datapublic class MemberTeamDto {
 private Long memberId;
 private String username;
 private int age;
 private Long teamId;
 private String teamName;
 
 @QueryProjection
 public MemberTeamDto(Long memberId, String username, int age, Long teamId,
String teamName) {
 this.memberId = memberId;
 this.username = username;
 this.age = age;
 this.teamId = teamId;
 this.teamName = teamName;
 }
}

@QueryProjection 을 추가했다. QMemberTeamDto 를 생성하기 위해 ./gradlew compileQuerydsl을 한번 실행하자.

 

 

참고: @QueryProjection 을 사용하면 해당 DTO가 Querydsl을 의존하게 된다. 이런 의존이 싫으면, 해당 에노테이션을 제거하고, Projection.bean(), fields(), constructor() 을 사용하면 된다.

 

 

회원 검색 조건

@Data
public class MemberSearchCondition {
 //회원명, 팀명, 나이(ageGoe, ageLoe)
 private String username;
 private String teamName;
 private Integer ageGoe;
 private Integer ageLoe;
 }

 

 

동적쿼리 - Builder 사용

Builder를 사용한 예제

//Builder 사용
//회원명, 팀명, 나이(ageGoe, ageLoe)
public List<MemberTeamDto> searchByBuilder(MemberSearchCondition condition) {
 BooleanBuilder builder = new BooleanBuilder();
 
 if (hasText(condition.getUsername())) {
 builder.and(member.username.eq(condition.getUsername()));
 }
 
 if (hasText(condition.getTeamName())) {
 builder.and(team.name.eq(condition.getTeamName()));
 }
 
 if (condition.getAgeGoe() != null) {
 builder.and(member.age.goe(condition.getAgeGoe()));
 }
 
 if (condition.getAgeLoe() != null) {
 builder.and(member.age.loe(condition.getAgeLoe()));
 }
 
 return queryFactory
 .select(new QMemberTeamDto(
 member.id,
 member.username,
 member.age,
 team.id,
 team.name))
 .from(member)
 .leftJoin(member.team, team)
 .where(builder)
 .fetch();
}

오류 정정 : 강의 영상에서는 member.id.as("memberId") 라고 적었는데, QMemberTeamDto 는 생성자를 사용하기 때문에 필드 이름을 맞추지 않아도 된다. 따라서 member.id 만 적으면 된다.

 

조회 예제 테스트

@Test
public void searchTest() {
 Team teamA = new Team("teamA");
 Team teamB = new Team("teamB");
 em.persist(teamA);
 em.persist(teamB);
 Member member1 = new Member("member1", 10, teamA);
 Member member2 = new Member("member2", 20, teamA);
 Member member3 = new Member("member3", 30, teamB);
 Member member4 = new Member("member4", 40, teamB);
 em.persist(member1);
 em.persist(member2);
 em.persist(member3);
 em.persist(member4);
 
 MemberSearchCondition condition = new MemberSearchCondition();
 condition.setAgeGoe(35);
 condition.setAgeLoe(40);
 condition.setTeamName("teamB");
 
 List<MemberTeamDto> result = memberJpaRepository.searchByBuilder(condition);
 assertThat(result).extracting("username").containsExactly("member4");
}

 

 

 

출처 : 김영한 JPA 스프링 데이터 강의