QueryDSL 정리 - 2

동적 쿼리 (Dynamic Query)

입력한 값에 따라 유연하게 생성되는 쿼리

• 이름만 있다면 이름으로 조건 조회

• 이메일도 있으면 이름 + 이메일이 조건으로 조회 …

BooleanBuilder, BooleanExpression

BooleanBuilder

여러 조건을 추가하여 하나씩 쌓아가며 만드는 동적 쿼리 패턴

@Repository
@RequiredArgsConstructor
public class UserRepositoryImpl implements UserRepository {
    private final JPAQueryFactory queryFactory;
    
		@Transactional(readOnly = true)
		@Override
		public List<UserSearchResponse> searchUserByMultiCondition(UserSearchRequest request) {
		    BooleanBuilder builder = new BooleanBuilder();
		
		    if (request.getUsername() != null && !request.getUsername().isBlank()) {
		        builder.and(user.username.contains(request.getUsername()));
		    }
		
		    if (request.getEmail() != null && !request.getEmail().isBlank()) {
		        builder.and(user.email.endsWith(request.getEmail()));
		    }
		
		    if (request.getRole() != null) {
		        builder.and(user.roleEnum.eq(request.getRole()));
		    }
		
		    return queryFactory
		            .select(new QUserSearchResponse(
		                    user.username,
		                    user.email,
		                    user.roleEnum))
		            .from(user)
		            .where(builder)
		            .orderBy(user.username.asc())
		            .fetch();
		}
}

BooleanExpression

여러 조건을 명시하여 꺼내 사용하는 동적 쿼리 패턴

@Repository
@RequiredArgsConstructor
public class UserRepositoryImpl implements UserRepository {
    private final JPAQueryFactory queryFactory;
	
	@Transactional(readOnly = true)
	@Override
	public List<UserSearchResponse> searchUserByMultiConditionV2(UserSearchRequest request) {
	    return queryFactory
	            .select(new QUserSearchResponse(
	                    user.username
	                    , user.email
	                    , user.roleEnum
	            )).from(user)
	            .where(
	                    userNameContains(request.getUsername())
	                    , userEmailContains(request.getEmail())
	                    , userRoleEq(request.getRole())
	            ).orderBy(user.username.asc())
	            .fetch();
	}
	
	private BooleanExpression userNameContains(String username) {
	    return username != null ? user.username.contains(username) : null;
	}
	
	private BooleanExpression userEmailContains(String email) {
	    return email != null ? user.email.contains(email) : null;
	}
	
	private BooleanExpression userRoleEq(UserRoleEnum role) {
	    return role != null ? user.roleEnum.eq(role) : null;
	}
}

복잡한 조절이 필요하면 BooleanBuilder 를, 재사용이 잦고 간단한 동적 제어가 필요하면 BooleanExpression 을 사용한다

QueryDSL 에서의 페이징 처리

컨트롤러 메서드에서 Pageable 파라미터를 가져간 후

PageImpl 로 구현하는 전체 큰 방안은 동일하다

// Controller
@GetMapping("/search/page")
public ResponseEntity<Page<UserSearchResponse>> searchUserByUsernameWithPage(UserSearchRequest request, Pageable pageable) {
    return ResponseEntity.ok(userService.searchUserListPage(request, pageable));
}

// Service
@Transactional
public Page<UserSearchResponse> searchUserListPage(UserSearchRequest request, Pageable pageable) {
    return userRepository.searchUserByMultiConditionPage(request, pageable);
}

// Repository Interface
public interface UserRepository {
    Page<UserSearchResponse> searchUserByMultiConditionPage(UserSearchRequest request, Pageable pageable);
}

// Repository Implement
@Repository
@RequiredArgsConstructor
public class UserRepositoryImpl implements UserRepository {
    private final JPAQueryFactory queryFactory;

    private BooleanExpression userNameContains(String username) {
        return username != null ? user.username.contains(username) : null;
    }

    private BooleanExpression userEmailContains(String email) {
        return email != null ? user.email.contains(email) : null;
    }

    private BooleanExpression userRoleEq(UserRoleEnum role) {
        return role != null ? user.roleEnum.eq(role) : null;
    }

    @Override
    public Page<UserSearchResponse> searchUserByMultiConditionPage(UserSearchRequest request, Pageable pageable) {
        // 실 데이터 값
        List<UserSearchResponse> result = queryFactory
                .select(new QUserSearchResponse(
                        user.username
                        , user.email
                        , user.roleEnum
                )).from(user)
                .where(
                        userNameContains(request.getUsername())
                        , userEmailContains(request.getEmail())
                        , userRoleEq(request.getRole())
                )
                .offset(pageable.getOffset())
                .limit(pageable.getPageSize())
                .orderBy(user.username.asc())
                .fetch();

        // 전체 데이터 갯수
        Long total = queryFactory
                .select(user.count())
                .from(user)
                .where(
                        userNameContains(request.getUsername())
                        , userEmailContains(request.getEmail())
                        , userRoleEq(request.getRole())
                ).fetchOne();

        // 전체 갯수가 null 인 경우는 방지
        if(total == null)
            total = 0L;

        // Page 객체로 변환 = PageImpl 객체 반환
        return new PageImpl<>(result, pageable, total); // 실 데이터 출력 값, 페이저블, 전체 데이터 갯수가 필요함
    }
}

PageImpl 전체를 반환하여 생성한 내역을 그대로?

그대로 사용하는 경우도 있겠지만,
대부분이 필요한 값만 추출하여 사용한 것으로 보인다

먼저 페이지 공통 응답 클래스를 만들어 감싸 사용하면 그만이다

public record PageResponse<T>(
    List<T> content,
    int currentPage,
    int totalPages,
    long totalElements,
    int size,
    boolean isLast
) {
    public static <T> PageResponse<T> register(Page<T> page) {
        return new PageResponse<>(
            page.getContent(),
            page.getNumber(),
            page.getTotalPages(),
            page.getTotalElements(),
            page.getSize(),
            page.isLast()
        );
    }
}

// Controller
@GetMapping("/search/page")
public ResponseEntity<PageResponse<UserSearchResponse>> searchUserByUsernameWithPage(UserSearchRequest request, Pageable pageable) {
    return ResponseEntity.ok(PageResponse.register(userService.searchUserListPage(request, pageable)));
}

QueryDSL 에서의 Lock 설정

@Repository
@RequiredArgsConstructor
public class EntityRepositoryImpl implements EntityRepositoryCustom {
    
    private final JPAQueryFactory queryFactory;
    
    public Optional<Entity> findByIdWithLock(Long id) {
        return Optional.ofNullable(
            queryFactory
                .selectFrom(entity)
                .where(entity.id.eq(id))
                .setLockMode(LockModeType.PESSIMISTIC_WRITE)
                .fetchOne()
        );
    }
}