Hibernate关联映射-one to many外键单向关联

以下是说明,1对多 单向外键关联 的实例.同样以person 和 address 为例.

 

 

为了方便测试,在原有的Hibernate框架上面,建立两个hbm.xml文件..

一个是Address_One_to_Many.hbm.xml,另外一个是Person_One_to_Many.hbm.xml。

然后,建立两个JavaBean 分别是:Address_One_to_Many 和 Person_One_to_Many

 

 

Person_One_to_Many具体内容如下:

/**
 * 1对多,单向关联
 * @author Administrator
 *
 */
public class Person_One_to_Many implements Serializable{
	
	private static final long serialVersionUID = -6313867775683964530L;
	private Integer id;
	private String name;
	private Integer age;
	
	//一个人，有多个地址;
	private Set<Address_One_to_Many> setAddress = new HashSet<Address_One_to_Many>();
      
                //getter 和 setter 方法省略	
}

 

 

Address_One_to_Many 具体代码如下:

/**
 * 
 * 一对多的关系;
 * @author Administrator
 *
 */
public class Address_One_to_Many implements Serializable{
	
	private static final long serialVersionUID = 3635140598485086087L;
	private Integer addressID;
	private String addressDetail;
               
                //getter 和 setter方法省略.
}

 

 

接下来就是配置Mapping映射文档.

Person_One_to_Many.hbm.xml 具体代码如下:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="pack.java.model">
	<class name="Person_One_to_Many" table="ZHT_Person_One_To_Many">
		<id name="id" column="ID" type="java.lang.Integer">
			<!-- mySql中主键id自动生成. -->
			<generator class="identity">
			</generator>
		</id>
		
		<!-- PERSON_ONE_TO_MANY属性的定义 -->
		<property name="name" column="NAME" type="java.lang.String"></property>
		<property name="age" column="AGE" type="java.lang.Integer"></property>
		
		<!-- 
			设置Address地址set集合,inverse = false代表主控制端; lazy=false代表不延迟加载.
			table=ADDRESS_ONE_TO_MANY 指定数据库的ADDRESSS一张表;方便关联查询;
			cascade=all 支持所有的级联操作;
		-->
		<set name="setAddress" inverse="false" lazy="false" table="ADDRESS_ONE_TO_MANY" cascade="all">
			<!-- 确定关联的外键列,可以任意取个名字;-->
			<key column="id" not-null="false"></key>
			<!-- 1个人多对应多个地址,所以class指向的是Address -->
			<one-to-many class="Address_One_to_Many"/>
		</set>
	</class>
</hibernate-mapping>

 

 

Address_One_to_Many.hbm.xml：

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
                                   "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="pack.java.model">
 <class name="Address_One_to_Many" table="ADDRESS_ONE_TO_MANY">
  <id column="ADDRESS_ID" name="addressID" type="java.lang.Integer">
   <generator class="identity"/>
  </id>
  
  <!-- ADDRESS_ONE_TO_MANY属性的定义; -->
  <property  lazy="false" name="addressDetail" column="ADDRESS_DETAIL" not-null="true"/>
 </class>
</hibernate-mapping>

 

 

配置完之后,记得在Hibernate.cfg.xml中加上 刚才新建xxx.hbm.xml文件的映射地址:

比如:

<mapping resource="pack/java/model/Address_One_to_Many.hbm.xml"/>
<mapping resource="pack/java/model/Person_One_to_Many.hbm.xml"/>

 

 

最后,在建立一个Test类进行测试刚刚配置的1对多的映射关系.

package pack.java.test;
import java.io.Serializable;
import java.util.Set;
import org.hibernate.Session;
import pack.java.hibernate.HibernateSessionFactory;
import pack.java.model.Address_One_to_Many;
import pack.java.model.Person_One_to_Many;
/**
 * 
 * Hibernate 测试类; 一对多外键单向关联;
 * @author ZhouHaiTao
 *
 */
public class HibernateDemoOneToMany {
	public static void main(String[] args) {
		HibernateDemoOneToMany hibernateDemoOneToMany = new HibernateDemoOneToMany();
		//保存地址;
		hibernateDemoOneToMany.saveAddress();
		
		//保存人物;
		hibernateDemoOneToMany.savePerson();
		
		//根据Person id查询person；
		hibernateDemoOneToMany.loadPersonByID(1);
	}
	
	/**
	 * 保存Address地址;
	 */
	private void saveAddress(){
		Session session = getSession();
		Address_One_to_Many address1 = new Address_One_to_Many();
		address1.setAddressDetail("湖南省株洲市");
	
		Address_One_to_Many address2 = new Address_One_to_Many();
		address2.setAddressDetail("广东省深圳市");
		
		Address_One_to_Many address3 = new Address_One_to_Many();
		address3.setAddressDetail("湖北省武汉市");
		
		//开始事务;
		session.beginTransaction().begin();
		//单独保存地址;
		session.save(address1);
		session.save(address2);
		session.save(address3);
		//提交事务;
		session.beginTransaction().commit();
		
		//关闭session;
		closeSession(session);
	}
	
	/**
	 * 保存Person,并且给Person指定多个地址;
	 */
	private void savePerson(){
		//获取session;
		Session session = getSession();
		Person_One_to_Many person1 = new Person_One_to_Many("李四",23);
		Person_One_to_Many person2 = new Person_One_to_Many("张三",23);
		
		Address_One_to_Many address1 = new Address_One_to_Many();
		address1.setAddressDetail("湖南省株洲市");
	
		Address_One_to_Many address2 = new Address_One_to_Many();
		address2.setAddressDetail("广东省深圳市");
		
		Address_One_to_Many address3 = new Address_One_to_Many();
		address3.setAddressDetail("湖北省武汉市");
		
		session.beginTransaction().begin();
		
		//给添加person1对象添加两个地址;
		person1.getSetAddress().add(address1);
		person1.getSetAddress().add(address2);
		
		//给person2对象，添加一个地址;
		person2.getSetAddress().add(address3);
		session.save(person1);
		session.save(person2);
		session.beginTransaction().commit();
		
		//关闭session;
		closeSession(session);
	}
	
	
	/**
	 * 根据person id查询出，person对象，以及地址;
	 * @param id
	 */
	private void loadPersonByID(Serializable id){
		Session session = getSession();
		Person_One_to_Many personOneToMany = (Person_One_to_Many) session.load(Person_One_to_Many.class, id);
		System.out.println("打印出Person中的属性信息:");
		System.out.println(personOneToMany.getId()+","+personOneToMany.getName()+","+personOneToMany.getAge());
		Set<Address_One_to_Many> addressOneToManies = personOneToMany.getSetAddress();
		
		System.out.println("\n打印出Address中的信息:");
		for(Address_One_to_Many  addressOneToMany : addressOneToManies){
			System.out.println(addressOneToMany.getAddressID()+","+addressOneToMany.getAddressDetail());
		}
		closeSession(session);
	}
	
	/**
	 * 创建session;
	 * @return
	 */
	private static Session getSession(){
		return HibernateSessionFactory.getSession();
	}
	
	/**
	 * 创建session;
	 * @return
	 */
	private static void closeSession(Session session){
		session.close();
	}
}

 

 

测试之后,可以在MySql中查看数据数据是否正常插入成功..

 

以下是控制台输出的信息,代表成功插入数据库:

 

打印出Person中的属性信息:
1,周海涛,23

打印出Address中的信息:
5,湖南省株洲市
4,广东省深圳市