스프링 데이터 JPA와 Querydsl

스프링 데이터 JPA Repository로 변경

package study.querydsl.repository;

import org.springframework.data.jpa.repository.JpaRepository;
import study.querydsl.domain.Member;

import java.util.List;

public interface MemberRepository extends JpaRepository<Member, Long> {
    List<Member> findByUsername(String username);
}

사용자 정의 리포지토리

인터페이스에 직접 queryDsl을 다 적어줄수는 없다. 따라서 customRepository를 만들고, 이를 JpaRepository에 상속을 해주면 된다.

커스텀 인터페이스

public interface MemberRepositoryCustom {
    List<MemberTeamDto> search(MemberSearchCondition condition);
}

인터페이스 구현

@RequiredArgsConstructor
public class MemberRepositoryImpl implements MemberRepositoryCustom{

    private final JPAQueryFactory queryFactory;

    @Override
    //회원명, 팀명, 나이(ageGoe, ageLoe)
    public List<MemberTeamDto> search(MemberSearchCondition condition) {
        return queryFactory
                .select(new QMemberTeamDto(
                        member.id,
                        member.username,
                        member.age,
                        team.id,
                        team.name))
                .from(member)
                .leftJoin(member.team, team)
                .where(usernameEq(condition.getUsername()),
                        teamNameEq(condition.getTeamName()),
                        ageGoe(condition.getAgeGoe()),
                        ageLoe(condition.getAgeLoe()))
                .fetch();
    }

    private Predicate usernameEq(String username) {
        return hasText(username) ?  member.username.eq(username) : null;
    }

    private Predicate teamNameEq(String teamName) {
        return hasText(teamName)  ? team.name.eq(teamName) : null;
    }

    private Predicate ageGoe(Integer ageGoe) {
        return ageGoe != null ? member.age.goe(ageGoe) : null;
    }

    private Predicate ageLoe(Integer ageLoe) {
        return ageLoe != null ? member.age.loe(ageLoe) : null;
    }
}

상속

package study.querydsl.repository;

import org.springframework.data.jpa.repository.JpaRepository;
import study.querydsl.domain.Member;

import java.util.List;

public interface MemberRepository extends JpaRepository<Member, Long>, MemberRepositoryCustom{
    List<Member> findByUsername(String username);
}

혹은, 쿼리조회용 리포지토리를 아예 하나 따로 분리해서 서비스 리포지토리와 쿼리 리포지토리를 구분해서 관리하는것도 하나의 방법이다.

페이징

심플 페이징

@Override
    public Page<MemberTeamDto> searchPageSimple(MemberSearchCondition condition, Pageable pageable) {
        QueryResults<MemberTeamDto> results = queryFactory
                .select(new QMemberTeamDto(
                        member.id,
                        member.username,
                        member.age,
                        team.id,
                        team.name))
                .from(member)
                .leftJoin(member.team, team)
                .where(usernameEq(condition.getUsername()),
                        teamNameEq(condition.getTeamName()),
                        ageGoe(condition.getAgeGoe()),
                        ageLoe(condition.getAgeLoe()))
                .offset(pageable.getOffset())
                .limit(pageable.getPageSize())
                .fetchResults();

        List<MemberTeamDto> content = results.getResults();
        long total = results.getTotal();
        return new PageImpl<>(content, pageable, total);
    }

pageable을 이용해서 offset, limit를 설정하고 Page를 반환한다.

카운트와 컨텐츠의 분리

@Override
    public Page<MemberTeamDto> searchPageComplex(MemberSearchCondition condition,
                                                 Pageable pageable) {
        List<MemberTeamDto> content = queryFactory
                .select(new QMemberTeamDto(
                        member.id,
                        member.username,
                        member.age,
                        team.id,
                        team.name))
                .from(member)
                .leftJoin(member.team, team)
                .where(usernameEq(condition.getUsername()),
                        teamNameEq(condition.getTeamName()),
                        ageGoe(condition.getAgeGoe()),
                        ageLoe(condition.getAgeLoe()))
                .offset(pageable.getOffset())
                .limit(pageable.getPageSize())
                .fetch();
        
        long total = queryFactory
                .select(member)
                .from(member)
                .leftJoin(member.team, team)
                .where(usernameEq(condition.getUsername()),
                        teamNameEq(condition.getTeamName()),
                        ageGoe(condition.getAgeGoe()),
                        ageLoe(condition.getAgeLoe()))
                .fetchCount();
        
        return new PageImpl<>(content, pageable, total);
    }

전체 카운트 조회를 최적화 하는 방법이다.

카운트 쿼리 최적화

        JPAQuery<Member> countQuery = queryFactory
                .select(member)
                .from(member)
                .leftJoin(member.team, team)
                .where(usernameEq(condition.getUsername()),
                        teamNameEq(condition.getTeamName()),
                        ageGoe(condition.getAgeGoe()),
                        ageLoe(condition.getAgeLoe()));

        return PageableExecutionUtils.getPage(content, pageable, () -> countQuery.fetchCount());

조건에 따라 페이지 쿼리를 날릴지, 토탈카운트를 날릴지 결정해준다.

조회용 컨트롤러

@RestController
@RequiredArgsConstructor
public class MemberController {

    private final MemberRepository memberRepository;

    @GetMapping("/v1/members")
    public List<MemberTeamDto> searchMemberV1(MemberSearchCondition condition) {
        return memberRepository.search(condition);
    }

    @GetMapping("/v2/members")
    public Page<MemberTeamDto> searchMemberV2(MemberSearchCondition condition, Pageable pageable) {
        return memberRepository.searchPageSimple(condition, pageable);
    }

    @GetMapping("/v3/members")
    public Page<MemberTeamDto> searchMemberV3(MemberSearchCondition condition, Pageable pageable) {
        return memberRepository.searchPageComplex(condition, pageable);
    }
}

스프링은 페이저블을 쿼리 파라미터로 받을 수 있다.

정렬

스프링 data의 정렬을 dsl이 맞춰서 쓰기가 상당히 어렵다.