JPA Repository와 Querydsl

1. 순수 JPA Repository -> Querydsl

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@Repository
public class MemberJpaRepository {

    private final EntityManager em;
    private final JPAQueryFactory queryFactory;

    public MemberJpaRepository(EntityManager em) {
        this.em = em;
        this.queryFactory = new JPAQueryFactory(em);
    }

    public void save(Member member){
        em.persist(member);
    }

    public Optional<Member> findById(Long id){
        Member findMember = em.find(Member.class, id);
        return Optional.ofNullable(findMember);
    }

    public List<Member> findAll_Querydsl(){
        return  queryFactory
                .select(member)
                .from(member)
                .fetch();
    }

    public List<Member> findAll(){
        return em.createQuery("select m from Member m", Member.class).getResultList();
    }

    public List<Member> findByUsername_Querydsl(String username){
        return queryFactory
                .selectFrom(member)
                .where(member.username.eq(username))
                .fetch();
    }

    public List<Member> findByUsername(String username){
        return em.createQuery("select m from Member m where m.username = :username", Member.class)
                .setParameter("username", username)
                .getResultList();
    }
}

@SpringBootTest
@Transactional
class MemberJpaRepositoryTest {

    @Autowired
    EntityManager em;

    @Autowired MemberJpaRepository memberJpaRepository;

    @Test
    public void basicTest(){
        Member member = new Member("member1", 10);
        memberJpaRepository.save(member);

        Member findMember = memberJpaRepository.findById(member.getId()).get();
        assertThat(findMember).isEqualTo(member);

        List<Member> result1 = memberJpaRepository.findAll_Querydsl();
        assertThat(result1).containsExactly(member);

        List<Member> result2 = memberJpaRepository.findByUsername_Querydsl("member1");
        assertThat(result2).containsExactly(member);
    }
}

 

 

 

2. JPAQueryFactory 사용 방법?

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• 생성자로 EntityManager를 받아서 JPAQueryFactory에 넣어주거나
  • injection이 하나 ㅋㅋ
• 스프링 bean으로 등록
  • injfection 두 개.. 귀찮.. 

@SpringBootApplication
public class QuerydslApplication {

    public static void main(String[] args) {
        SpringApplication.run(QuerydslApplication.class, args);
    }

    @Bean
    JPAQueryFactory jpaQueryFactory(EntityManager em){
        return new JPAQueryFactory(em);
    }

}

    public MemberJpaRepository(EntityManager em, JPAQueryFactory queryFactory) {
        this.em = em;
        this.queryFactory = queryFactory;
    }

 

 

* 참고

JPAQueryFactory의 동시성 문제는 EntityManager에 의존함

Spring과 EntityManager를 엮어서 쓰면 Transaction 단위로 동시성 관계 없이 분리되어 동작함.

 

 

3. GitHub : 210904 Querydsl, Repository

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GitHub - bsh6463/Querydsl