使用JPA覆盖@MappedSuperclass中定义的@Id [英] Overriding @Id defined in a @MappedSuperclass with JPA

问题描述

我有一个AbstractEntity类，该类由应用程序中的所有实体扩展，并且基本上充当标识符提供程序.

I have a class AbstractEntity that is extended by all the entities in my application and basically acts as an Identifier provider.

@MappedSuperclass
public class AbstractEntity implements DomainEntity {

    private static final long serialVersionUID = 1L;

    /** This object's id */
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    protected long id;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name="creation_date", nullable = false, updatable=false)
    private Date creationDate = new Date();

    /**
     * @return the id
     */
    public long getId() {
        return this.id;
    }

    /**
     * @param id the id to set
     */
    public void setId(long id) {
        this.id = id;
    }
}

我现在有一种情况，我需要为几个实体类定义一个单独的ID，因为它们需要有一个自定义序列生成器.如何做到这一点?

I have a case now where I need to define a separate Id for couple of my Entity classes as these need to have a custom Sequence Generator. How can this be achieved?

@Entity
@Table(name = "sample_entity")
public class ChildEntity extends AbstractChangeableEntity {

    @Column(name = "batch_priority")
    private int priority;

    public int getPriority() {
        return priority;
    }

    public void setPriority(int priority) {
        this.priority = priority;
    }

}

推荐答案

您不能这样做.检查此 GitHub示例(如果需要).

You can't do it. Check this GitHub example if you want.

在基类中定义@Id后，将无法在子类中覆盖它，这意味着最好将@Id责任留给每个具体的类.

Once you define the @Id in a base class you won't be able to override it in a sub-class, meaning it's better to leave the @Id responsibility to each individual concrete class.

查看这篇文章以获取更多详细信息.

Check out this article for more details.

这篇关于使用JPA覆盖@MappedSuperclass中定义的@Id的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！