在spring + hibernate中保存creationTimestamp和updatedTime

Question

我需要用createdDate和updatedDate更新postgres DB，我尝试过使用方法1，但它插入的是空值。当我读到这篇文章时，似乎@prepersist注解在会话中不起作用。

所以我决定采用方法2: Hibernate @CreationTimeStamp Annotation，我添加了hibernate-Annotation maven依赖项，但@CreationTimeStamp没有解析，并给出了编译错误。

有人能建议我如何解决这个问题吗？

方法1使用@Entity和@Table注释的实体类

      public class Status{
      @Id
    @Column(name = "run_id")
    private int run_id; 

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

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name = "created_date" , updatable=false)
    private Date created;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name = "updated_date" ,  insertable=false)
    private Date updated;

    @PrePersist
    protected void onCreate() {
        created = new Date();
    }


    @PreUpdate
    protected void onUpdate() {
        updated = new Date();
    }
//Getters and setters here
}

实现类是

  sessionFactory.getCurrentSession().save(status);  

方法2使用@CreationTimeStamp和@updatedTimeStamp。但是maven依赖

<!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-annotations -->
<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-annotations</artifactId>
    <version>3.5.0-Final</version>
</dependency>

不会将这些注释添加到类路径中

Answer 1

使用session.save()方法而不是使用entitymanager有什么原因吗？我将发布一个使用entitymanager持久化和合并实体的应用程序示例。另外，我使用的是java.time.LocalDateTime而不是java.util.Date，这就是我不需要@Temporal的原因。

如果你想使用Entity管理器，这将会有帮助：Guide to the Hibernate EntityManager Entity How to use @PrePersist and @PreUpdate on Embeddable with JPA and Hibernate：

public abstract class AbstractEntity implements Serializable {
  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  @Column(updatable = false, nullable = false)
  private Long id;

  @Column
  private LocalDateTime createdTimestamp;

  @Column
  private LocalDateTime modifiedTimestamp;

  @Version
  private Long version;

  @PrePersist
  public void setCreationDateTime() {
    this.createdTimestamp = LocalDateTime.now();
  }

  @PreUpdate
  public void setChangeDateTime() {
    this.modifiedTimestamp = LocalDateTime.now();
  }
  //Getter and setter
}

抽象数据库服务类：

public abstract class AbstractDatabaseService {
  @PersistenceContext(name = "examplePU")
  protected EntityManager entityManager;
}

实体存储库接口示例：

public interface ExampleRepository {
  ExampleEntity save(ExampleEntity exampleEntity);
}

实体库实现示例：

public class ExampleRepositoryImpl extends AbstractDatabaseService implements ExampleRepository , Serializable {
  @Transactional
  @Override
  public ExampleEntity save(ExampleEntity exampleEntity) {
    ExampleEntity toPersist;
    // Updating an already existing entity
    if (exampleEntity.getId() != null) {
      toPersist = entityManager.find(ExampleEntity .class, exampleEntity.getId());
      // Omitted merging toPersist with the given exampleEntity through a mapper class here
    } else {
      toPersist = exampleEntity;
    }
    try {
      toPersist = entityManager.merge(toPersist);
    } catch (Exception e) {
      // Logging e
    }
    return toPersist;
  }
}

希望这能有所帮助。