1：Person类

public class Person {
 
 private int id;
 private String name;
 private IdCard idCard;
  public IdCard getIdCard() {
  return idCard;
 } public void setIdCard(IdCard idCard) {
  this.idCard = idCard;
 } public 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;
 }}

IdCard类

public class IdCard {
 
 private int id;
 private String cardNo;

 

public int getId() {
  return id;
 } public void setId(int id) {
  this.id = id;
 } public String getCardNo() {
  return cardNo;
 } public void setCardNo(String cardNo) {
  this.cardNo = cardNo;
 }}

 

2：配置文件

Person的配置文件
<hibernate-mapping >
  <class name="com.bjsxt.hibernate.Person" table="t_person">
     <id name="id">
         <generator class="native"></generator>
     </id>
     <property name="name"></property>
    <many-to-one name="idCard" unique="true"/>
  </class>
</hibernate-mapping> 
IdCard的配置文件
<hibernate-mapping >
  <class name="com.bjsxt.hibernate.IdCard" table="t_idcard">
     <id name="id">
         <generator class="native"/>
     </id>
     <property name="cardNo"></property>    
  </class>
</hibernate-mapping>3：测试程序
//
 public void testSave1(){
  Session session = null;
  try{
   session = HibernateUtils.getSession();
   session.beginTransaction();
   
   IdCard idCard = new IdCard();
   idCard.setCardNo("88888888888888");
   
   Person person = new Person();
   person.setIdCard(idCard);
   person.setName("aa");
   
   //不能成功保存，因为idCard是Transient状态
   session.save(person);
   
   session.getTransaction().commit();
   
  }catch(Exception e){
   e.printStackTrace();
   session.getTransaction().rollback();
  }finally{
   HibernateUtils.closeSession(session);
  } 
 }
 //首先保存IdCard，再保存Person
 public void testSave2(){
  Session session = null;
  try{
   session = HibernateUtils.getSession();
   session.beginTransaction();
   
   IdCard idCard = new IdCard();
   idCard.setCardNo("88888888888888");
   session.save(idCard);
   
   Person person = new Person();
   person.setIdCard(idCard);
   person.setName("aa");
   
   session.save(person);
   
   session.getTransaction().commit();
   
  }catch(Exception e){
   e.printStackTrace();
   session.getTransaction().rollback();
  }finally{
   HibernateUtils.closeSession(session);
  } 
 }
 //首先加载Person，再加载IdCard
 public void testLoad1(){
  Session session = null;
  try{
   session = HibernateUtils.getSession();
   session.beginTransaction();
  
   Person person = (Person)session.load(Person.class,5);
   System.out.println(person.getName());
   System.out.println(person.getIdCard().getCardNo());
    
   session.getTransaction().commit();
   
  }catch(Exception e){
   e.printStackTrace();
   session.getTransaction().rollback();
  }finally{
   HibernateUtils.closeSession(session);
  } 
 }

4：总结

hibernate一对一唯一外键关联映射（单向关联Person----->IdCard)

一对一唯一外键关联映射是多对一关联映射的特例

 可以采用<many-to-one>标签，指定多的一端的unique=true;这样就限制了多的一端
 的多重性为一，通过这种手段映射一对一唯一外键关联