java - Hibernate 一对一映射问题 - 级联功能不起作用

Question

我有以下 HBM 实体类:

1. Train.java、Ticket.java、Booking.java、Passenger.java

我在 Booking 和 Ticket 之间有一对一关系。请在下面找到 hibernate pojo 类:

@Entity
@Table(name = "TICKET_MASTER")
@Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
public class Ticket implements Serializable {

@Transient
private static final long serialVersionUID = 1L;

@Id
@GeneratedValue(strategy = GenerationType.AUTO, generator = "TICKET_SEQ")
@SequenceGenerator(name = "TICKET_SEQ", sequenceName = "TICKET_SEQ",  allocationSize = 1)
@Column(name = "TICKET_ID", nullable = false)
private Long ticketId;

@Column(name = "TICKET_NO", nullable = false)
private String ticketNo;

@OneToOne(mappedBy = "ticket",cascade=CascadeType.ALL)
private Booking booking;

@OneToMany(fetch = FetchType.LAZY, mappedBy = "ticket")
private Set<Passenger> passengers;

@ManyToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "TRAIN_ID", nullable = false)
private Train train;

//getters & setters
 }

@Entity
@Table(name = "BOOKING_MASTER")
@Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
public class Booking extends RMSEntity {
    private static final long serialVersionUID = 1L;

  @Id
  @GeneratedValue(strategy = GenerationType.AUTO, generator = "BOOKING_SEQ")
  @SequenceGenerator(name = "BOOKING_SEQ", sequenceName = "BOOKING_SEQ", allocationSize = 1)
  @Column(name = "BOOKING_ID", nullable = false)
  private Long bookingId;

  @Column(name = "BOOKING_NO", nullable = false)
  private String bookingNo;

  @OneToOne
  @JoinColumn(name = "TICKET_ID", referencedColumnName = "TICKET_ID")
  private Ticket ticket;

  //gettres & setters
 }

由于上述两个类之间出现问题，我将省略 Passenger 和 Train 的 pojo 类。

请在下面找到我的服务层代码:

@Transactional(readOnly = false, propagation = Propagation.REQUIRED, rollbackFor = { Throwable.class })
@Override
public void saveBookingDetails(PassengerDTO passengerDTO) {
    BeanUtils.copyProperties(passengerDTO, passenger);*/
    Train train = getDaoProvider().getTrainDao().find(passengerDTO.getTrainId());
    Ticket ticket = new Ticket();
    ticket.setTicketId((long) (Math.random() * 100));
    String ticketNo = UUID.randomUUID().toString().split("-")[0];
    ticket.setTicketNo(ticketNo);
    Booking booking = new Booking();
    String bookingNo = UUID.randomUUID().toString().split("-")[0];
    booking.setBookingId((long)(Math.random() * 100)); 
    booking.setBookingNo(bookingNo); 
    ticket.setBooking(booking); 
    ticket.setTrain(train); 
    getDaoProvider().getTicketDao().saveOrUpdate(ticket);
   }

我遇到以下异常:

Caused By: org.hibernate.exception.ConstraintViolationException: could not execute batch
at org.hibernate.exception.internal.SQLStateConversionDelegate.convert(SQLStateConversionDelegate.java:112)
at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:42)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:111)
at org.hibernate.engine.jdbc.batch.internal.BatchingBatch.performExecution(BatchingBatch.java:119)
at org.hibernate.engine.jdbc.batch.internal.BatchingBatch.doExecuteBatch(BatchingBatch.java:97)
Truncated. see log file for complete stacktrace
Caused By: java.sql.BatchUpdateException: ORA-01400: cannot insert NULL into ("SYSTEM"."TICKET_MASTER"."BOOKING_ID")

at oracle.jdbc.driver.OraclePreparedStatement.executeBatch(OraclePreparedStatement.java:12296)
at oracle.jdbc.driver.OracleStatementWrapper.executeBatch(OracleStatementWrapper.java:246)
at weblogic.jdbc.wrapper.PreparedStatement.executeBatch(PreparedStatement.java:197)
at org.hibernate.engine.jdbc.batch.internal.BatchingBatch.performExecution(BatchingBatch.java:110)
at org.hibernate.engine.jdbc.batch.internal.BatchingBatch.doExecuteBatch(BatchingBatch.java:97)
Truncated. see log file for complete stacktrace

我正在使用 Spring-Hibernate ORM 功能。

Answer 1

在双向关系中，你应该有一个从每一方到另一方的引用，你错过了在预订中注入(inject)车票，火车也是如此。

Booking booking = new Booking();
booking.setTicket(ticket);
train.setTicket(ticket);
String bookingNo = UUID.randomUUID().toString().split("-")[0];

另一件事，因为您在预订中的 id 是自动生成的，所以您不应该设置 id，hibernate 会根据持久性负责为其分配 id

String bookingNo = UUID.randomUUID().toString().split("-")[0];// this line should be removed
booking.setBookingId((long)(Math.random() * 100));//this line should be removed
ticket.setTicketId((long) (Math.random() * 100));//this line should be removed

同时删除 Ticket 的线路设置 ID。

此外，由于您正在使用序列生成，因此您需要将类型指定为序列而不是自动

@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "BOOKING_SEQ")