【7.4.2】基于主键的单向一对一的关联映射

1.公民表person和身份证表idcard

 

2.Person和IdCard类

public class Person {
	private int id;
	private String name;
	private int age;
	private IdCard idCard;
//get…set
}


public class IdCard{
	private int id;
	private String code;
	//get…set
}

　　

3.映射文件 

Person.hbm.xml

<?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.siggy.pojo">
	<class name="IdCard">
		<id name="id">
			<generator class="native"></generator>
		</id>
		<property name="code"/>
	</class>
</hibernate-mapping>

　　

IdCard.hbm.xml

<?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.siggy.pojo">
	<class name="Person">
		<id name="id">
			<!-- foreign表示引用外键 -->
			<generator class="foreign">
				<!-- 引用idCard属性所对应的主键 -->
				<param name="property">idCard</param>
			</generator>
		</id>
		<property name="name"/>
		<property name="age"/>
		<!-- 一对一 -->
		<one-to-one name="idCard" constrained="true" cascade="save-update"/>
	</class>
</hibernate-mapping>

　　

4.测试代码【测试testSave()方法】

package cn.siggy.test;

import java.sql.SQLException;

import javax.sql.rowset.serial.SerialException;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.junit.Test;

import cn.siggy.pojo.IdCard;
import cn.siggy.pojo.Person;
import cn.siggy.util.HibernateUtil;

public class HibernateTest {
	@Test
	public void testCreateDB(){
		Configuration cfg = new Configuration().configure();
		SchemaExport se = new SchemaExport(cfg);
		//第一个参数 是否生成ddl脚本  第二个参数  是否执行到数据库中
		se.create(true, true);
	}
	@Test
	public void testSave() throws HibernateException, SerialException, SQLException{
		Session session = null;
		Transaction tx = null;
		try{
			session = HibernateUtil.getSession();
			tx = session.beginTransaction();
			IdCard id1 = new IdCard();
			id1.setCode("320123231212112");
			IdCard id2 = new IdCard();
			id2.setCode("110231432423432");
			Person person1 = new Person();
			person1.setName("贾宝玉");
			person1.setAge(23);
			person1.setIdCard(id1);
			Person person2 = new Person();
			person2.setName("林黛玉");
			person2.setAge(22);
			person2.setIdCard(id2);
			Person person3 = new Person();
			person3.setName("薛宝钗");
			person3.setAge(21);
			person3.setIdCard(id2);
			session.save(person1);
			session.save(person2);
			//当保存person3出错
			//session.save(person3);
			tx.commit();
			
		}catch (HibernateException e) {
			if(tx!=null)
				tx.rollback();
			e.printStackTrace();
			throw e;
		}finally{
			HibernateUtil.closeSession();
		}
	}
	@Test
	public void testGet(){
		Session session = null;
		Transaction tx = null;
		try{
			session = HibernateUtil.getSession();
			tx = session.beginTransaction();
			//取数据
			tx.commit();
		}catch (HibernateException e) {
			if(tx!=null)
				tx.rollback();
			e.printStackTrace();
			throw e;
		}finally{
			HibernateUtil.closeSession();
		}
	}
}

　　

5.测试结果

1.运行testCreateDB()创建表时：

 

 

2.运行testSave()方法：【在保存person对象时先保存person对象中的idCard属性信息】