[Querydsl] 5. JPQL vs Querydsl 비교

안녕하세요.

이전에 만든 Entity를 CompileQuerydsl 하여 QType Class를 만들어줍니다.

• QuerydslBasicTest.java

  @SpringBootTest
  @Transactional
  public class QuerydslBasicTest {
  
    @Autowired
    EntityManager em;
  
    JPAQueryFactory queryFactory;
  
    @BeforeEach
    public void before() {
        queryFactory = new JPAQueryFactory(em); // 동시성 문제 해결됩니다.
  
        Team teamA = new Team("TEAM A");
        Team teamB = new Team("TEAM B");
        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);
    }
  
    @Test
    public void startJPQL() throws Exception {
  
        String query = "select m from Member m where m.username = :username";
        Member findMember = em.createQuery(query, Member.class)
                .setParameter("username", "member1")
                .getSingleResult();
  
        assertThat(findMember.getUsername()).isEqualTo("member1");
    }
  
    @Test
    public void startQuerydsl() throws Exception {
  
        QMember m = new QMember("m");
  
        Member findMember = queryFactory.selectFrom(m)
                .where(m.username.eq("member1"))
                .fetchOne();
  
        assertThat(findMember.getUsername()).isEqualTo("member1");
    }
  }

EntityManager 로 JPAQueryFactory 생성
Querydsl은 JPQL 빌더
JPQL: 문자(실행 시점 오류), Querydsl: 코드(컴파일 시점 오류)
JPQL: 파라미터 바인딩 직접, Querydsl: 파라미터 바인딩 자동 처리

감사합니다.

참고

www.inflearn.com/course/Querydsl-%EC%8B%A4%EC%A0%84#