使用 Crud 存储库保存具有嵌套对象的实体

Question

如何保存一个嵌套了另一个实体的实体？

回购

public interface ReservationRepository extends JpaRepository<Reservation, Integer> {
    Optional<Reservation> findReservationBySection_SectionId(int id);
}

服务

@Service
public class ReservationService {
    private final Logger logger = LoggerFactory.getLogger(getClass().getName());
    @Autowired
    private ReservationRepository reservationRepository;
    @Autowired
    private SectionRepository sectionRepository;
    @Autowired
    private UserRepository userRepository;


    public Reservation addReservation(Reservation reservation) {
        Reservation newReservation = new Reservation();
        newReservation.setCount(reservation.getCount());
        newReservation.setCustom_section_name(reservation.getCustom_section_name());
        newReservation.setFrom_time(reservation.getFrom_time());
        newReservation.setTo_time(reservation.getTo_time());
        newReservation.setSection(sectionRepository.getOne(reservation.getSection().getSectionId()));
        newReservation.setUser(userRepository.getOne(reservation.getUser().getUserId()));
        logger.info(newReservation.toString());
        return reservationRepository.save(newReservation);
    }

}

用户实体

User
    @Id
    @GeneratedValue
    @Column(name = "user_id")
    private int userId;

    @Column(name = "name")
    private String name;
    
    @Column(name="email", unique = true)
    private String email;

    @JsonIgnore
    @Column(name = "password")
    private String password;

    @Column(name = "phone")
    private String phone;

    @Column(name = "expiration_date")
    private Timestamp expirationDate;

部分实体

Section
    @Id
    @GeneratedValue
    @Column(name = "section_id")
    private int sectionId;

    @Column(name = "section_name")
    private String sectionName;

    @OneToOne
    @JoinColumn(name="room_id")
    private Section roomId;

预订实体

    @Id
    @GeneratedValue
    @Column(name = "reservation_id")
    private int reservationId;

    @ManyToOne
    @MapsId("section_id")
    @JoinColumn(name = "section_id")
    private Section section;

    @ManyToOne
    @MapsId("user_id")
    @JoinColumn(name = "user_id")
    private User user;

    @Column(name = "count")
    private int count;

    @Column(name = "custom_section_name")
    private String custom_section_name;

    @Column(name = "from_time")
    private Timestamp from_time;


    @Column(name = "to_time", unique = true)
    private Timestamp to_time;

预期结果：

想要在数据库中保存包含部分和用户的预订。像这样：

实际结果：

已创建预订但缺少 section_id 和 user_id

SQL 数据库表的 section_id 和 user_id 不为空，因为它们的表中有主键。 如果需要，将提供更多信息。

Answer 1

如果 Reservation 拥有与 Section 的关系，则需要将 Cascade 添加到关系中。当您持久化 Reservation 时，Hibernate 会拦截您还想持久化一个 Section 并将其对应的引用附加到 Reservation 实体的事实。

你可以添加

    @ManyToOne(cascade = CascadeType.ALL)
    @JoinColumn(name = "section_id")
    private Section section;

您可以根据需要修改Cascade类型（例如：如果您不想级联删除操作）

这是一篇好文章： https://www.baeldung.com/jpa-cascade-types