HibernateUtil

//刚开始学hibernate 的第一课，我就整理了我的HibernateUtil工具类

package com.uitl;

import java.util.List;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.cfg.Configuration;

import com.entity.DeptBean;

public class HibernateUtil {

private final static SessionFactory sessionFactory;

static {

    //根据hibernate.cfg.utl得到一个SessionFactory

    sessionFactory = new Configuration().configure().buildSessionFactory();

}

public static SessionFactory getSessionFactory(){

 return sessionFactory;

}

/**1、添加   2、删除  3、修改*/

public static void update(Object obj,int style){

  SessionFactory sessionFactory =HibernateUtil.getSessionFactory(); //获得session工厂

  Session session=sessionFactory.openSession(); //引用session  

  if(style==1)

     session.save(obj);//添加

  else if(style==2)

 session.delete(obj);//删除

  else if(style==3)

  session.update(obj);//修改

           session.beginTransaction().commit(); //提交事务

           session.close();

}

/**查询单个*/

public static Object queryById(Class bean ,int id) {

 SessionFactory sessionFactory =HibernateUtil.getSessionFactory(); //获得session工厂
 Session session=sessionFactory.openSession(); //引用session  
 Object obj=session.get(bean, id);
         session.beginTransaction().commit(); //提交事务
         session.close();  

         return obj;

}

/** 查询所有*/

public static List queryAll(String beanName) {

 SessionFactory sessionFactory =HibernateUtil.getSessionFactory();   //获得session工厂

 Session session=sessionFactory.openSession();      //引用session  

 List list=session.createQuery("from "+beanName+"").list();

         session.beginTransaction().commit();     //提交事务

         session.close();

         return list;    

}

}