simpleproperquerytest.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.Query;
import org.hibernate.Session;

import junit.framework.TestCase;

public class SimpleProperQueryTest extends TestCase {
	public void testQuery1()
	{
		Session session = null;
		try{
			session = HibernateUtils.getSession();
			session.beginTransaction();
			
			List students = session.createQuery( "select name from Student" ).list();
			for( Iterator ite = students.iterator() ; ite.hasNext() ; ){
				String name = ( String )ite.next();
				System.out.println( name );
			}
			
			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();
			
			//查询多个元素，返回的是数组
			List students = session.createQuery( "select id,name from Student" ).list();
			for( Iterator ite = students.iterator() ; ite.hasNext() ; ){
				Object[] object = ( Object[] )ite.next();
				System.out.println( object[ 0 ] + "," + object[ 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();
			
			//向Student提供构造函数可以查询Student对象
			//此时list是对象集合
			List students = session.createQuery( "select new Student(id,name) from Student" ).list();
			for( Iterator ite = students.iterator() ; ite.hasNext() ; ){
				Student student = ( Student )ite.next();
				System.out.println( student.getId() + "," + student.getName() );
			}
			
			session.getTransaction().commit();
			
		}catch( Exception e ){
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally{
			HibernateUtils.closeSession(session);
		}
	}
	
	public void testQuery4()
	{
		Session session = null;
		try{
			session = HibernateUtils.getSession();
			session.beginTransaction();
			
			//使用别名查询,也可以用as命名别名
			List students = session.createQuery( "select s.id, s.name from Student s" ).list();
			for( Iterator ite = students.iterator() ; ite.hasNext() ; ){
				Object[] object = ( Object[] )ite.next();
				System.out.println( object[ 0 ] + "," + object[ 1 ] );
			}
			
			session.getTransaction().commit();
			
		}catch( Exception e ){
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally{
			HibernateUtils.closeSession(session);
		}
	}
}