리포지토리 지원 - QuerydslRepositorySupport

1. QuerydslRepositorySupport 

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• EntityManager 주입해줌.
• Querdsl 유틸리티 클래스 : Helper instance to ease access to Querydsl JPA query API.
• from절부터 시작 가능.

@Repository
public abstract class QuerydslRepositorySupport {

	private final PathBuilder<?> builder;

	private @Nullable EntityManager entityManager;
	private @Nullable Querydsl querydsl;

 

 

2. from절부터 시작

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• 바로 from부터 시작. select를 마지막에

        //from절부터 시작.
        List<MemberTeamDto> result = from(member)
                .leftJoin(member.team, team)
                .where(
                        usernameEq(condition.getUsername()),
                        teamNameEq(condition.getTeamName()),
                        ageGoe(condition.getAgeGoe()),
                        ageLoe(condition.getAgeLoe()))
                .select(new QMemberTeamDto(
                        member.id.as("memberId"),
                        member.username,
                        member.age,
                        team.id.as("teamId"),
                        team.name.as("teamName")))
                .fetch();

 

3. Paging처리 쉬워짐.

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• getQuerydsl().applyPagingnation(pageable, query)를 실행하면
• 해당 메서드에서 offset, limit 넣어줌 ㅋㅋ 편리함. 흠.. 이게 다임.

    @Override
    public Page<MemberTeamDto> searchPageSimple2(MemberSearchCondition condition, Pageable pageable) {

        JPQLQuery<MemberTeamDto> jpaQuery = from(member)
                .leftJoin(member.team, team)
                .where(
                        usernameEq(condition.getUsername()),
                        teamNameEq(condition.getTeamName()),
                        ageGoe(condition.getAgeGoe()),
                        ageLoe(condition.getAgeLoe()))
                .select(new QMemberTeamDto(
                        member.id.as("memberId"),
                        member.username,
                        member.age,
                        team.id.as("teamId"),
                        team.name.as("teamName")));

        JPQLQuery<MemberTeamDto> query = getQuerydsl().applyPagination(pageable, jpaQuery);//offset, limit 넣어줌.
        query.fetchResults();

 

 

 

4. 단점

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• Querydsl 3.x 버전을 대상으로 만듬
• Querydsl 4.x에 나온 JPAQueryFactory로 시작할 수 없음
• select로 시작할 수 없음 (from으로 시작해야함)
• QueryFactory 를 제공하지 않음
• 스프링 데이터 Sort 기능이 정상 동작하지 않음
• 흠.........