hibernate annotation 继承 外键

[Azrael99999]

xx.java

package bean;

import java.io.Serializable;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="XX")
public class xx implements Serializable  {
	private int id;
	private String name;

	@Id
	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	@Column
	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}
}

yy.java

package bean;

import java.io.Serializable;

import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.MappedSuperclass;

@MappedSuperclass
public class yy implements Serializable {
	private int id;
	private xx x;

	@Id
	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	@ManyToOne
	@JoinColumn(name="xid")
	public xx getX() {
		return x;
	}

	public void setX(xx x) {
		this.x = x;
	}

}

zz.java

package bean;

import java.io.Serializable;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Table;

@Entity
@Table(name="ZZ")
public class zz extends yy implements Serializable {
	private String comment;

	@Column
	public String getComment() {
		return comment;
	}

	public void setComment(String comment) {
		this.comment = comment;
	}
}

这样为什么就生产了 一张表 XX?

[y591174893]

这个是因为annotation默认的是xml配置中的subclass方式继承，不过hibernate推荐用union-class，不过现在我还不知道怎么写，楼主知道了回复我一声，谢谢！