hibernate的crud操作

package com.yuzd.hibernate;

import java.util.Date;

import junit.framework.TestCase;

import org.hibernate.Session;

import com.yuzd.util.HbmUtils;

public class SessionTest extends TestCase {
    
    public void addUser(){
        Session session = null;
        try {
            session = HbmUtils.getSession();
            session.beginTransaction();
            User user = new User();
            user.setName("aaa");
            user.setPassword("aaa");
            user.setCreateTime(new Date());
            user.setExpireTime(new Date());
            session.save(user);
            session.getTransaction().commit();
        } catch (Exception e) {
            e.printStackTrace();
            session.getTransaction().rollback();
        }finally{
            HbmUtils.closeSession(session);
        }
    }
    
    public void getUser(){
        Session session =null;
        try {
            session = HbmUtils.getSession();
            session.beginTransaction();
            //get方法是通过主键id来查找的，hibernate中get方法建议在事物中使用
            //如果get方法查询不出结果则返回null
            User user = (User) session.get(User.class, "402881e941c503b30141c503b7440001");
            System.out.println(user.getName());
            user.setName("李四");
            session.save(user);
            session.getTransaction().commit();
        } catch (Exception e) {
            e.printStackTrace();
            session.getTransaction().rollback();
            
        }finally{
            HbmUtils.closeSession(session);
        }
    }
    
    public void loadUser(){
        Session session = null;
        try {
            session = HbmUtils.getSession();
            session.beginTransaction();
            //只有在真正使用的时候才会发出sql指令，lazy延迟加载
            //如果数据库中没有对应的数据的话就会抛出异常
            User user = (User) session.load(User.class, "402881e941c5a1630141c5a482330001");
            System.out.println(user.getName());//这句的时候才会真正的去数据库查询
            session.getTransaction().commit();
        } catch (Exception e) {
            e.printStackTrace();
            session.getTransaction().rollback();
        }finally{
            HbmUtils.closeSession(session);
        }
    }
    
    public void updateUser(){
        Session session = null;
        try {
            session = HbmUtils.getSession();
            session.beginTransaction();
            User user = new User();
            user.setId("402881e941c5a1630141c5a482330001");
            user.setName("王五");
            //这样改的话会把其他的属性设置成null，一般采用的方法是先load然后更改属性值
            session.update(user);
            session.getTransaction().commit();
        } catch (Exception e) {
            e.printStackTrace();
            session.getTransaction().rollback();
        }finally{
            HbmUtils.closeSession(session);
        }
    }
    
    public void deleteUser(){
        Session session = null;
        try {
            session = HbmUtils.getSession();
            session.beginTransaction();
            //先load然后再delete
            User user = (User) session.load(User.class, "402881e941c5a1630141c5a482330001");
            session.delete(user);
            session.getTransaction().commit();
        } catch (Exception e) {
            e.printStackTrace();
            session.getTransaction().rollback();
        }finally{
            HbmUtils.closeSession(session);
        }
    }
}