hibernate 关于联合主键

-----------------------------映射文件----------------------------------------------

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
 "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="cn.gdpe.compositeKey" auto-import="true"> 
 <class name="User">  
  <!-- 复合主键映射 -->
  <composite-id name="keys">//联合主键对象与实体类定义的引用名必须一致
       <key-property name="userName" type="string"></key-property>
       <key-property name="address" type="string"></key-property>
  </composite-id>
  <property name="age" type="int"></property>    
 </class>

</hibernate-mapping>

-------------------------------联合主键类----------------------------------------------

package cn.gdpe.compositeKey;

import java.io.Serializable;

// 复合主键类
public class CompositeKeys implements Serializable{
 private String userName;
 private String address;
 public String getUserName() {
  return userName;
 }
 public void setUserName(String userName) {
  this.userName = userName;
 }
 public String getAddress() {
  return address;
 }
 public void setAddress(String address) {
  this.address = address;
 }
 
}

------------------------------实体对象类---------------------------------

public class User {

 // 名字跟地址，不会重复
 private CompositeKeys keys;
 private int age;
 
 public CompositeKeys getKeys() {
  return keys;
 }
 public void setKeys(CompositeKeys keys) {
  this.keys = keys;
 }
 public int getAge() {
  return age;
 }
 public void setAge(int age) {
  this.age = age;
 } 
}

-----------------------------总结-----------------------------------------

    联合主键  就是把需要设为主键的属性    提取出来    重写定义一个主键类（就是一个普通类）   联合主键作为此类的属性  

    在实体类中 引用该类   映射文件中如上设置。