OneToOne annotation 双向关联

来源：互联网发布：淘宝海选报名编辑：程序博客网时间：2024/06/05 10:58

package com.hibernate.entity;import java.io.Serializable;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.Id;import javax.persistence.OneToOne;@Entitypublic class Husband implements Serializable {/** *  */private static final long serialVersionUID = 2476364405175138004L;private int id;private String name;private Wife wife;@Id@GeneratedValuepublic int getId() {return id;}public String getName() {return name;}@OneToOnepublic Wife getWife() {return wife;}public void setId(int id) {this.id = id;}public void setName(String name) {this.name = name;}public void setWife(Wife wife) {this.wife = wife;}}

package com.hibernate.entity;import java.io.Serializable;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.Id;import javax.persistence.OneToOne;@Entitypublic class Wife implements Serializable {/** *  */private static final long serialVersionUID = 5270130768836331730L;private int id;private String name;private Husband husband;@Id@GeneratedValuepublic int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}@OneToOne(mappedBy="wife")public Husband getHusband() {return husband;}public void setHusband(Husband husband) {this.husband = husband;}}

注意：Wife类的getHusband()上用了mappedBy"wife"

这个意思是说，我这里的OneToOne就不用管了，只用Husband里的getWife()上的OneToOne关系

生成的表为Husband参考Wife，有了wifeid，才能有Husband

Husband为这个关系的拥有者

如果Wife类的getHusband()只有@OneToOne，没有mappedBy，那么生成的两张表都会有对方的外键，造成外键冗余。

阅读全文

0 0