hibernate 008 一对一唯一外键双向关联映射

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

一对一唯一外键关联双向，需要在另一端（idcard），添加<one-to-one>标签，指示hibernate如何加载
其关联对象，默认根据主键加载person，外键关联映射中，因为两个实体采用的是person的外键维护的关系，
所以不能指定主键加载person，而要根据person的外键加载，所以采用如下映射方式：
<one-to-one name="person" property-ref="idCard"/>

1.IdCard.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.bjsxt.hibernate.IdCard" table="t_idcard">
<id name="id">
<generator class="native"/>
</id>
<property name="cardNo"/>
<one-to-one name="person" property-ref="idCard"/>
</class>
</hibernate-mapping>

Person.hbmm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC 
	"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
	"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
	<class name="com.bjsxt.hibernate.Person" table="t_person">
		<id name="id">
			<generator class="native"/>
		</id>
		<property name="name"/>
		<many-to-one name="idCard" unique="true"/>
	</class>
</hibernate-mapping>

2.单元测试类

package com.bjsxt.hibernate;

import org.hibernate.Session;

import junit.framework.TestCase;

public class One2OneTest extends TestCase {

	public void testSave1() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			
			IdCard idCard = new IdCard();
			idCard.setCardNo("88888888888888");
			
			Person person = new Person();
			person.setName("菜10");
			person.setIdCard(idCard);
			
			//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);
		}
	}		
	
	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.setName("菜10");
			person.setIdCard(idCard);
			
			session.save(person);
			
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}			
	public void testLoad1() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			
			Person person = (Person)session.load(Person.class, 2);
			System.out.println("person.name=" + person.getName());
			System.out.println("idCard.cardNo=" + person.getIdCard().getCardNo());
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}		
	
	public void testLoad2() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			
			IdCard idCard = (IdCard)session.load(IdCard.class, 1);
			System.out.println("idcard.cardNo=" + idCard.getCardNo());
			System.out.println("idcard.person.name=" + idCard.getPerson().getName());
			
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}		
	
}