說明：

一、例子是一個組有許多使用者，但一個使用者只能屬於一個組

二、本次使用的Hibernate版本是hibernate-release-4.3.11.Final.

先寫Annotation版本：

實體類：

Group.java：

package com.buaa.hibernate.bean;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;

@Entity
@Table(name="t_group")
public class Group {
	private int id;
	private String name;
	private Set<User> users = new HashSet<User>();
	
	@OneToMany(mappedBy="group")
	public Set<User> getUsers() {
		return users;
	}
	public void setUsers(Set<User> users) {
		this.users = users;
	}
	@Id
	@GeneratedValue
	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;
	}
	
}
 

package com.buaa.hibernate.bean;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;

@Entity
@Table(name="t_user")
public class User {
	private int id;
	private String name;
	private Group group;
	
	@ManyToOne
	@JoinColumn(name="groupId") //多的一方加外來鍵
	public Group getGroup() {
		return group;
	}
	public void setGroup(Group group) {
		this.group = group;
	}
	@Id
	@GeneratedValue
	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;
	}
	

}
 

User.hbm.xml:

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

<hibernate-mapping package="com.buaa.hibernate.bean">

	<class name="User" table="t_user">
	    <id name="id">
			<generator class="native" />
		</id>
		<property name="name"/>
		<many-to-one name="group" column="groupId"></many-to-one>
	</class>

	<class name="Group" table="t_group">
		<id name="id">
			<generator class="native" />
		</id>
		<property name="name"/>
		<set name="users">
			<key column="groupId"></key>			
			<one-to-many class="User" />
		</set>
	</class>
	
</hibernate-mapping>
 

下面是Hibernate配置檔案：hibernate.cfg.xml：

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration SYSTEM 
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
   <session-factory>
	   
	   <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
	
	   <!-- Assume test is the database name -->
	   <property name="connection.url">jdbc:mysql://localhost/test</property>
	   <property name="connection.username">root</property>
	   <property name="connection.password">123456</property>
	   
	   <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
	   <property name="show_sql">true</property>
	   
	   <property name="format_sql">true</property>
	   <!-- <property name="hbm2ddl.auto">create</property> -->
	
		<!-- 
		 -->
		<mapping resource="com/buaa/hibernate/bean/User.hbm.xml"/>
		 <!-- 
		<mapping class="com.buaa.hibernate.bean.Group"/>
		<mapping class="com.buaa.hibernate.bean.User"/>
		  -->
	</session-factory>
</hibernate-configuration>

MyTest.java：

package com.buaa.hibernate.bean;

import java.util.HashSet;
import java.util.Set;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.junit.Test;


public class MyTest {
	@Test
	public void test(){
		User user1 = new User();
		user1.setName("u1");
		User user2 = new User();
		user2.setName("u2");
		Set<User> users = new HashSet<User>();
		users.add(user1);
		users.add(user2);
		Group group = new Group();
		group.setName("A");
		group.setUsers(users);
		user1.setGroup(group);
		user2.setGroup(group);
		
		Configuration configuration = new Configuration().configure();
		ServiceRegistry service = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();
		SessionFactory factory = configuration.buildSessionFactory(service);
		Session session = factory.openSession();
		session.beginTransaction();
		session.save(user1);
		session.save(user2);
		session.save(group);
		session.getTransaction().commit();
		session.close();
		factory.close();
	}
	
	@Test
	public void SchemaExportTest(){
		Configuration cfg = new Configuration().configure();
		//第一個引數是否將sql語句輸出到控制檯，第二個引數是否在資料庫中生成對應的表格
		new SchemaExport(cfg).create(true,true);
	}
}