public Optional<Member> findById(Long id) {
Member member = em.find(Member.class, id);
return Optional.ofNullable(member);
}
Optional을 사용하여 Member를 감싸고
return으로 Optional.ofNullable(member)를 사용해준다.
ofNullable:
If a value is present, returns the value, otherwise throws NoSuchElementException.
Member member = memberJpaRepository.findById(member1.getId()).get();
꺼낼때는 꼭 .get()으로 꺼내는 것을 잊지말자