我的实体类有共同的属性。他们必须有Id - 序列long
号
Date
createdDate显示何时将实体的元组添加到 DB 和Date
lastModifiedDate属性,显示最后一次修改元组的时间。
我使用 JPA 2.1。,休眠 4.3.6.Final
<depedencies>
<!-- Hibernate -->
<dependency>
<groupId>org.hibernate.javax.persistence</groupId>
<artifactId>hibernate-jpa-2.1-api</artifactId>
<version>1.0.0.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-validator</artifactId>
<version>5.1.1.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>4.3.6.Final</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.34</version>
</dependency>
</dependencies>
所以我制作了具有关键属性的公共类:
@Embeddable
public class AbstractArticle implements Serializable {
private static final long serialVersionUID = 895868474989692116L;
@Nonnull
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(nullable = false)
private long id;
@Temporal(TemporalType.TIMESTAMP)
@Column(name = "createdDate", nullable = false)
private Date createdDate;
@Temporal(TemporalType.TIMESTAMP)
@Column(name = "lastModifiedDate", nullable = false)
private Date lastModifiedDate;
public AbstractArticle() {
}
... //getters and setters
}
和另一个使用这个公共键值的类
@Entity
public class BBCNews{
@Nonnull
@Column(name = "newsId", nullable = false)
private long newsId;
@Nonnull
@Column(name = "title", nullable = false)
private String title;
@CheckForNull
@Column(name = "description", nullable = true)
private String description;
@Id
private AbstractArticle abstractArticle;
public BBCNews() {
}
...//getters and setters
好的,一切都很好,但是长 id AbstractArticle 是相同的 0,数据库中的所有元组都以 0 作为 id。这是什么意思。有任何想法吗?