joinquerytest.java

实现一些hibernate底层的东西

package com.bjsxt.hibernate;

import java.util.Iterator;
import java.util.List;

import org.hibernate.Session;

import junit.framework.TestCase;

/**
 * 连接查询
 * @author Administrator
 *
 */
public class JoinQueryTest extends TestCase {

	public void testQuery1() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			
			//List students = session.createQuery("select c.name, s.name from Student s join s.classes c").list();
			List students = session.createQuery("select c.name, s.name from Student s inner join s.classes c").list();
			for (Iterator iter=students.iterator(); iter.hasNext();) {
				Object[] obj = (Object[])iter.next();
				System.out.println(obj[0] + "," + obj[1]);
			}
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}

	public void testQuery2() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();

			List students = session.createQuery("select c.name, s.name from Classes c left join c.students s").list();
			for (Iterator iter=students.iterator(); iter.hasNext();) {
				Object[] obj = (Object[])iter.next();
				System.out.println(obj[0] + "," + obj[1]);
			}
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}
	
	public void testQuery3() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();

			List students = session.createQuery("select c.name, s.name from Classes c right join c.students s").list();
			for (Iterator iter=students.iterator(); iter.hasNext();) {
				Object[] obj = (Object[])iter.next();
				System.out.println(obj[0] + "," + obj[1]);
			}
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}
	
}