[Chapter 08] EntityManager

[BvrPark]

1. @PrePersist

p.572에 보면 persist()나 remove()와 관련된 여러 어노테이션들이 나와있는데 우리가 JPA를 쓰게 되면 명시적으로 EntityManager를 쓰지 않고 JpaRepository를 상속받아서 쓰게됩니다.
그러면 EntityManager의 persist()역할을 JpaRepository의 save()가 대체할 것 같은데, 그러면 p.572에 나와있는 @PrePersist를 예로 들었을때, Service단에서 save()를 사용하면 그때, @PrePersist가 달린 메서드를 먼저 실행하고 save()를 실행한다는 의미가 맞을까요?

[corock]

네 맞습니다. 책에 나오는 예제로 간단하게 테스트해 볼 수 있습니다.

XxxApplication.java

@Slf4j
@SpringBootApplication
public class XxxApplication {

    public static void main(String[] args) {
        ConfigurableApplicationContext ctx = SpringApplication.run(CorockApplication.class, args);
        HotelService hotelService = ctx.getBean(HotelService.class);

        HotelCreateRequest request = new HotelCreateRequest();
        request.setName("The LINE LA");
        request.setAddress("3515 Wilshire Blvd, Los Angeles, CA 90010");
        request.setPhoneNumber("+12133817411");
        request.setRoomCount(8);

        hotelService.createHotel(request);
    }

}

HotelService.java

@Service
@RequiredArgsConstructor
public class HotelService {

    private final HotelRepository hotelRepository;

    @Transactional(readOnly = false, isolation = Isolation.SERIALIZABLE)
    public HotelCreateResponse createHotel(HotelCreateRequest createRequest) {
        HotelEntity hotelEntity = HotelEntity.of(createRequest.getName(), createRequest.getAddress(),
                                                 createRequest.getPhoneNumber());

        int roomCount = createRequest.getRoomCount();
        List<HotelRoomEntity> hotelRoomEntities = IntStream.range(0, roomCount)
                .mapToObj(i -> HotelRoomEntity.of("ROOM-" + i, HotelRoomType.DOUBLE, BigDecimal.valueOf(100)))
                .collect(Collectors.toList());
        hotelEntity.addHotelRooms(hotelRoomEntities);

        HotelEntity savedHotelEntity = hotelRepository.save(hotelEntity);

        return HotelCreateResponse.of(savedHotelEntity.getHotelId());
    }

}

HotelAuditListener.java

@Slf4j
public class HotelAuditListener {

    @PrePersist
    public void testBeforeCreated(HotelEntity hotelEntity) {
        log.info("before HotelEntity created. HotelEntity: {}", hotelEntity);
    }

    @PostPersist
    public void logWhenCreated(HotelEntity hotelEntity) {
        log.info("after HotelEntity created. HotelEntity: {}", hotelEntity);
    }

}

hotel-pre-persist.json

{
  "address": "3515 Wilshire Blvd, Los Angeles, CA 90010",
  "hotelId": null,
  "hotelRoomEntities": [
    "HotelRoomEntity(hotelRoomId=null, hotelId=null, roomNumber=ROOM-0, roomType=DOUBLE, originalPrice=100)",
    "HotelRoomEntity(hotelRoomId=null, hotelId=null, roomNumber=ROOM-1, roomType=DOUBLE, originalPrice=100)",
    "HotelRoomEntity(hotelRoomId=null, hotelId=null, roomNumber=ROOM-2, roomType=DOUBLE, originalPrice=100)",
    "HotelRoomEntity(hotelRoomId=null, hotelId=null, roomNumber=ROOM-3, roomType=DOUBLE, originalPrice=100)",
    "HotelRoomEntity(hotelRoomId=null, hotelId=null, roomNumber=ROOM-4, roomType=DOUBLE, originalPrice=100)",
    "HotelRoomEntity(hotelRoomId=null, hotelId=null, roomNumber=ROOM-5, roomType=DOUBLE, originalPrice=100)",
    "HotelRoomEntity(hotelRoomId=null, hotelId=null, roomNumber=ROOM-6, roomType=DOUBLE, originalPrice=100)",
    "HotelRoomEntity(hotelRoomId=null, hotelId=null, roomNumber=ROOM-7, roomType=DOUBLE, originalPrice=100)"
  ],
  "name": "The LINE LA",
  "phoneNumber": "+12133817411",
  "roomCount": 8,
  "status": "READY",
  "createdBy": null,
  "createdDate": "2023-11-11T19:11:07.053588+09:00[Asia/Seoul]",
  "modifiedBy": null,
  "modifiedDate": null
}

hotel-post-persist.json

{
  "address": "3515 Wilshire Blvd, Los Angeles, CA 90010",
  "hotelId": 6,
  "hotelRoomEntities": [
    "HotelRoomEntity(hotelRoomId=null, hotelId=null, roomNumber=ROOM-0, roomType=DOUBLE, originalPrice=100)",
    "HotelRoomEntity(hotelRoomId=null, hotelId=null, roomNumber=ROOM-1, roomType=DOUBLE, originalPrice=100)",
    "HotelRoomEntity(hotelRoomId=null, hotelId=null, roomNumber=ROOM-2, roomType=DOUBLE, originalPrice=100)",
    "HotelRoomEntity(hotelRoomId=null, hotelId=null, roomNumber=ROOM-3, roomType=DOUBLE, originalPrice=100)",
    "HotelRoomEntity(hotelRoomId=null, hotelId=null, roomNumber=ROOM-4, roomType=DOUBLE, originalPrice=100)",
    "HotelRoomEntity(hotelRoomId=null, hotelId=null, roomNumber=ROOM-5, roomType=DOUBLE, originalPrice=100)",
    "HotelRoomEntity(hotelRoomId=null, hotelId=null, roomNumber=ROOM-6, roomType=DOUBLE, originalPrice=100)",
    "HotelRoomEntity(hotelRoomId=null, hotelId=null, roomNumber=ROOM-7, roomType=DOUBLE, originalPrice=100)"
  ],
  "name": "The LINE LA",
  "phoneNumber": "+12133817411",
  "roomCount": 8,
  "status": "READY",
  "createdBy": null,
  "createdDate": "2023-11-11T19:11:07.053588+09:00[Asia/Seoul]",
  "modifiedBy": null,
  "modifiedDate": null
}