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
