many2manytest.java

hibernate 关联实例包括（一对一关联）一对多关联(单向

package com.bjsxt.hibernate;

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

import org.hibernate.Session;

import junit.framework.TestCase;

public class Many2ManyTest extends TestCase {
	
	/**
	 * 从Role端保存用户和角色
	 *
	 */
	public void testSaveMany2Many() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			Role role1 = new Role();
			role1.setName("角色1");
			
			Role role2 = new Role();
			role2.setName("角色2");
			
			Role role3 = new Role();
			role3.setName("角色3");
			
			User user1 = new User();
			user1.setName("用户1");
			session.save(user1);
			
			User user2 = new User();
			user2.setName("用户2");
			session.save(user2);
			
			User user3 = new User();
			user3.setName("用户3");
			session.save(user3);
			
			Set user12 = new HashSet();
			user12.add(user1);
			user12.add(user2);
			
			Set user23 = new HashSet();
			user23.add(user2);
			user23.add(user3);
			
			
			Set user123 = new HashSet();
			user123.add(user1);
			user123.add(user2);
			user123.add(user3);
			
			
			role1.setUsers(user12);
			session.save(role1);
			
			role2.setUsers(user23);
			session.save(role2);
			
			role3.setUsers(user123);
			session.save(role3);
			
			session.getTransaction().commit();
			
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}
	
	/**
	 * 从Role加载数据
	 *
	 */
	public void testLoadMany2Many() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			Role role = (Role)session.load(Role.class, 2);
			System.out.println("角色:" + role.getName());
			Set users = role.getUsers();
			for (Iterator iter = users.iterator(); iter.hasNext();) {
				User user = (User)iter.next();
				System.out.println("用户:" + user.getName());
			}
		}catch(Exception e) {
			e.printStackTrace();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}
	
	/**
	 * 从User加载数据
	 *
	 */
	public void testLoadMany2Many1() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			User user = (User)session.load(User.class, 2);
			System.out.println("用户:" + user.getName() + "拥有的角色");
			Set roles = user.getRoles();
			for (Iterator iter = roles.iterator(); iter.hasNext();) {
				Role role = (Role)iter.next();
				System.out.println(role.getName());
			}
			
		}catch(Exception e) {
			e.printStackTrace();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}
	
}