Javaweb常用工具类及配置文件备份

做一个代码备份，以后常用到的。

hibernate工具类备份

package com.dly.service;
/*
 * hibernate获取session 的工具类
 */
import java.io.Serializable;

import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.Session;

public final class HibernateUtil {
	private static SessionFactory sessionFactory;
    public static SessionFactory getSessionFactory() {
		return sessionFactory;
	}
    private HibernateUtil(){
}
static{
	Configuration cfg=new Configuration();
	cfg.configure();//配置文件名
	sessionFactory=cfg.buildSessionFactory();
}
public static Session getSession(){
	return sessionFactory.openSession();
	
}
/**
 * 添加信息
 * @param entity
 */
public static void add(Object entity){
	Session s=null;
	Transaction tx=null;
	try{
		s=HibernateUtil.getSession();
		tx=s.beginTransaction();
		s.save(entity);
		tx.commit();
	}finally{
		if(s!=null){
			s.close();
		}
	}
}
/**
 * 更新信息
 * @param entity
 */

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

/**
 * 删除信息
 * @param entity
 */
public static void delete(Object entity){
	Session s=null;
	Transaction tx=null;
	try{
		s=HibernateUtil.getSession();
		tx=s.beginTransaction();
		s.delete(entity);
		tx.commit();
	}finally{
		if(s!=null){
			s.close();
		}
	}
}
/**
 * 根据id查询
 * @param clazz
 * @param id
 * @return
 */

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

}

　　操作数据库举例：

package com.dly.service;

import java.util.List;

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



import com.dly.entity.Users;

public class UserDao {
	public static String queryByname(String name){
		Session s=null;
		String result=null;
		//System.out.println("调用了");
		try{
			s=HibernateUtil.getSession();
			String hql="from Users as user where user.username=:username";//里面User是类名，不是表名，为类名起别名user，查询的是对象
		    Query query=s.createQuery(hql);
		    query.setString("username", name);
		   Users u=(Users) query.uniqueResult();//确定只有一个数据，限制用户名唯一时使用
		  // System.out.println(u.getUsername());
		   if(u!=null){
			   result=u.getUsername();
			   System.out.println(result);
		   }
		  return result;
		}finally{
			if(s!=null){
				s.close();
			}
		}
	}
	public static Users queryByusername(String username,String pwd){
		Users user=null;
		Session s=null;
		try{
			s=HibernateUtil.getSession();
			String hql="from Users as users  where users.username=:username";//里面User是类名，不是表名，为类名起别名user，查询的是对象
		    Query query=s.createQuery(hql);
		    query.setString("username", username);
		    List<Users>list =query.list();
		    for(Users users:list){
				  String u=users.getUsername();
				  String p=users.getPassword();
				  if(u.equals(username)&&p.equals(pwd)){
					 user=users;
				  }
			   }
		   return user;
		}finally{
			if(s!=null){
				s.close();
			}
		}
	}
	

}

　　servlet常用代码举例：

package com.dly.servlet;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.json.JSONArray;
import com.dly.entity.Shop;
import com.dly.service.BuyCarDao;
import com.dly.service.HibernateUtil;


@WebServlet("/BuyCarList")
public class BuyCarList extends HttpServlet {
	private static final long serialVersionUID = 1L;
   // Class clazz=BuyCar.class;
    Class<Shop> clazz=Shop.class;
    List<Shop> shop=new ArrayList<Shop>();
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doPost(request, response);
	}
	
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		response.setContentType("text/html;charset=UTF-8");
		int userid=Integer.parseInt(request.getParameter("userid"));
		List<Integer> list=new ArrayList<Integer>();
		list=BuyCarDao.querayByuserid(userid);
		Iterator<Integer> it=list.iterator();
		List<Shop>shop=new ArrayList<Shop>();
		while(it.hasNext()){
			int shopid=(Integer) it.next();
			shop.add((Shop) HibernateUtil.get(clazz, shopid));
		}
		JSONArray shoplist=new JSONArray(shop);
		response.getWriter().println(shoplist.toString());
	}

}

　　

package com.dly.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.dly.entity.BuyCar;
import com.dly.service.BuyCarDao;
import com.dly.service.HibernateUtil;

@WebServlet("/AddBuyCar")
public class AddBuyCar extends HttpServlet {
	private static final long serialVersionUID = 1L;
   
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doPost(request, response);
	}

	
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		response.setContentType("text/html;charset=UTF-8");
		BuyCar buycar;
		int  shopid = Integer.parseInt(request.getParameter("shopid"));
		int userid=Integer.parseInt(request.getParameter("userid"));
		BuyCar result =BuyCarDao.queryByshopid(shopid);
		if(result==null){
			buycar=new BuyCar();
			buycar.setShopid(shopid);
			buycar.setUserid(userid);
			HibernateUtil.add(buycar);
			response.getWriter().print("添加成功");
			response.getWriter().flush();
		}else{
			response.getWriter().print("该商品已在购物车中");
			response.getWriter().flush();
		}
	}

}

　　

hibernate配置文件编写

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
	"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
	"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
 	<session-factory>
	<!-- 映射文件  -->
	 <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
	      <property name="connection.url">jdbc:mysql://localhost:3306/trade?useUnicode=true&characterEncoding=UTF-8</property>
		<property name="connection.username">root</property>
		<property name="connection.password"></property> 
		<property name="dialect"> org.hibernate.dialect.MySQLDialect</property>
	<mapping resource="com/dly/entity/Users.hbm.xml"/>

 	</session-factory>
 </hibernate-configuration>

　　Users.hbm.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC 
	"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
	"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
 <hibernate-mapping package="com.dly.entity">
 	<class name="Users" table="users" >
 		<!-- id值 -->
 		<id name="userid" type="int" length="11">
			<generator class="native"/>
		</id>
		<property name="username" type="string" length="32" column="username"></property>
		<property name="password" type="string" length="32" column="password"></property>
		<property name="school" type="string" length="64" column="school"></property>
		<property name="userphone" type="string" length="32" column="userphone"></property>
 	</class>
 </hibernate-mapping>

　　此代码正在完善中。。。。。。