JAVA/JPA
순수 JPA레포지토리의 페이징과 스프링 데이터 JPA레포지토리의 페이징.
gracelove91
2020. 2. 10. 22:44
순수 JPA레포지토리의 페이징과 스프링 데이터 JPA레포지토리의 페이징.
순수 JPA레포지토리
MemberJpaRepository.class
public List<Member> findByPage(int age, int offset, int limit) {
return em.createQuery("select m from Member as m" +
" where m.age = :age" +
" order by m.username asc", Member.class)
.setParameter("age", age)
.setFirstResult(offset)
.setMaxResults(limit)
.getResultList();
}
MemberJpaRepositoryTest.class
@Transactional
@Test
void paging() {
memberJpaRepository.save(new Member("member1", 10));
memberJpaRepository.save(new Member("member2", 10));
memberJpaRepository.save(new Member("member3", 10));
memberJpaRepository.save(new Member("member4", 10));
memberJpaRepository.save(new Member("member5", 10));
memberJpaRepository.save(new Member("member6", 10));
int age = 10;
int offset = 0;
int limit = 3;
List<Member> members = memberJpaRepository.findByPage(age, offset, limit); //member1, member2, member3
for (Member member : members) {
System.out.println("member = " + member);
}
long totalCount = memberJpaRepository.totalCountByAge(age);
assertEquals(3, members.size());
assertEquals(6, totalCount);
}
스프링 데이터 JPA 레포지토리
MemberRepository.class
Page<Member> findByAge(int age, Pageable pageable);
MemberRepositoryTest.class
- Sorting과 Pageable로 페이징을 추상화했다.
@Transactional
@Test
void paging() {
memberRepository.save(new Member("member1", 10));
memberRepository.save(new Member("member2", 10));
memberRepository.save(new Member("member3", 10));
memberRepository.save(new Member("member4", 10));
memberRepository.save(new Member("member5", 10));
memberRepository.save(new Member("member6", 10));
int age = 10;
int offset = 0;
int limit = 3;
PageRequest pageRequest = PageRequest.of(offset, limit, Sort.by(Sort.Direction.ASC, "username"));
Page<Member> members = memberRepository.findByAge(age, pageRequest); //member1, member2, member3
Page<MemberDto> map = members.map(member -> new MemberDto(member.getId(), member.getUsername(), null));
for (MemberDto memberDto : map) {
System.out.println("memberDto = " + memberDto);
}
List<Member> content = members.getContent();
long totalElements = members.getTotalElements();
assertEquals(6, totalElements);
assertEquals("member1", content.get(0).getUsername());
}
Count 같은 통계쿼리 쓸 때 주의할 점
Page<T>
타입의 경우 count 쿼리 또한 날린다.연관관계 있다면 Left Outer Join 해서 count 쿼리 날리기 떄문에 무겁다 떄문에 countQuery를 커스텀해주자.
@Query(value = "select m from Member m left join fetch m.team as t", countQuery = "select count(m.username) from Member as m") Page<Member> findByAge(int age, Pageable pageable);