hibernate复习第（一）天

package cn.itcast.hibernate;

import java.util.Date;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.junit.Test;

import cn.itcast.hibernate.domain.User;

public class Base {
    
    public static void main(String[] args) {
        /*
         * hibernate初始化的过程，这个过程一般只做一次
         * 所以我们一般做一个工具类
         */
//        Configuration cfg=new Configuration();
//        cfg.configure();
//        SessionFactory sf=cfg.buildSessionFactory();
//        Session s=sf.openSession();
        
        Session s=HibernateUtil.getSession();
        //JDBC是自动提交的，但是hibernate的缺省将这个功能关闭，必须自己开启使用事务才会生效
        //如果必须要开启提交事务就可以操作数据库数据的话，注意一下你的表结构，看你的引擎
        User user=new User();
        user.setName("zhangSan");
        user.setBirthday(new Date());
        
//        Transaction tx=s.beginTransaction();
//        s.save(user);
//        tx.commit();
//        s.close();
//        System.out.println("end");
        addUser(user);
        System.out.println("id:"+user.getId());
        
//        User u=getUser(user.getId());
        User u=(User) s.load(User.class, user.getId());
        
        System.out.println("name:"+u.getName());
        
    }
    
    static void addUser(User user){//比较规范的hibernate的一个写法
        Session s=null;
        Transaction tx=null;
        try{
            s=HibernateUtil.getSession();;
            tx=s.beginTransaction();
            s.save(user);
//            s.persist(user);
            user.setName("new name");//这个user是持久状态
            user.setBirthday(new Date());
            tx.commit();
        }catch(HibernateException e){
            if(tx!=null) tx.rollback();
            throw e;
        }finally{
            if(s!=null) s.close();
        }
    }
    
    static void addUser1(User user){//可以简写成为这个样子，接到异常自动向外抛，如果数据库没有得到提交请求会自动回滚
        Session s=null;
        Transaction tx=null;
        try{
            s=HibernateUtil.getSession();;
            tx=s.beginTransaction();
            s.save(user);
            tx.commit();
        }finally{
            if(s!=null) s.close();
        }
    }
    
    @Test
    public void fun1(){
        System.out.println(getUser(1));
    }
    public static User getUser(int id){
        Session s=null;
        User user=null;
        try{
            s=HibernateUtil.getSession();
            user=(User) s.get(User.class, 1);
//            user=(User) s.load(User.class,1);//这里会报错
        }finally{
            if(s!=null) s.close();
        }
        return user;
    }

}
    public static void add(Object entity){
        Session s=null;
        Transaction tx=null;
        try{
            s=getSession();
            tx=s.beginTransaction();
            s.save(entity);
            tx.commit();
        }catch(HibernateException e){
            tx.rollback();
            throw e;
        }finally{
            if(s!=null) s.close();
        }
    }

    public static void delete(Object entity){
        Session s=null;
        Transaction tx=null;
        try{
            s=getSession();
            tx=s.beginTransaction();
            s.delete(entity);
            tx.commit();
        }catch(HibernateException e){
            tx.rollback();
            throw e;
        }finally{
            if(s!=null) s.close();
        }
    }

    public static void update(Object entity){
        Session s=null;
        Transaction tx=null;
        try{
            s=getSession();
            tx=s.beginTransaction();
            s.update(entity);
            tx.commit();
        }catch(HibernateException e){
            tx.rollback();
            throw e;
        }finally{
            if(s!=null) s.close();
        }
    }

    public static Object get(Class clazz,Serializable id){
        Session s=null;
        try{
            s=getSession();
            return s.get(clazz, id);
        }catch(HibernateException e){
            throw e;
        }finally{
            if(s!=null) s.close();
        }
    } 

    public static Object load(Class clazz,Serializable id){
        Session s=null;
        try{
            s=getSession();
            return s.load(clazz, id);
        }catch(HibernateException e){   
            throw e;
        }finally{
            if(s!=null) s.close();
        }
    } 

package cn.itcast.hibernate;

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

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

import cn.itcast.hibernate.domain.User;

public class QueryTest {
    public static void main(String[] args) {
        User user=new User();
        user.setBirthday(new Date());
        user.setName("name");
        HibernateUtil.add(user);
        
        System.out.println(query("name"));
    }
    
    static User query(String name){
        Session s=null;
        try{
            s=HibernateUtil.getSession();
//            String hql="from User as user where user.name=?";
            String hql="from User as user where user.name=:n";
            Query query=s.createQuery(hql);
//            query.setString(0, name);//下标从0开始
            query.setString("n", name);
            
            //设置结果集的范围，可用来分页
            query.setFirstResult(200);
            query.setMaxResults(10);
            
            List<User> list=query.list();//executeQuery()
            User user=(User) query.uniqueResult();
//            for(Iterator<User> it=list.iterator();it.hasNext();){
//                User user=it.next();
//                list.add(user);
////                System.out.println(user);
//            }
//            return list.get(0);
            return user;
        }finally{
            if(s!=null) s.close();
        }
    }
}

package cn.itcast.hibernate;

import java.util.Date;
import java.util.List;

import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.criterion.Restrictions;

import cn.itcast.hibernate.domain.User;

public class Cri {
    public static void main(String[] args) {
        cri("name");
    }
    
    static void cri(String name){
        Session s=null;
        try{
            s=HibernateUtil.getSession();
            Criteria c=s.createCriteria(User.class);//条件查询，很面向对象的方式。这个接口相当于一个容器
            c.add(Restrictions.eq("name", name));//添加约束条件
            c.add(Restrictions.lt("birthday", new Date()));
            
            c.setFirstResult(0);
            c.setMaxResults(10);
            List<User> list=c.list();
            
            User u=(User)c.uniqueResult();
            System.out.println(u);
            
            for(User user:list){
                System.out.println(user.getName());
            }
        }finally{
            if(s!=null) s.close();
        }
    }
}