goodslistaction.java

一个购物网站

package dataDisposal;

import java.util.*;

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class GoodsListAction extends HttpServlet{
     public void doGet(HttpServletRequest request,HttpServletResponse response)
		throws ServletException,IOException{		
		HttpSession session=request.getSession(); 
		PrintWriter out=response.getWriter();
		ServletContext application=getServletConfig().getServletContext();
				
		if(application.getAttribute("goodsList") == null ){
							 //第一次请求此页面，需要初始化goodsList
							 	//但同时要注意：如果对数据库的商品列表进行了更新，则同时必须
							 	//对application中的goodsList进行更新！！
			String sql="";
			ArrayList goodsList=null;
			
			sql = "select * from goodsInfo order by tradeTimes desc " ;
			
			GoodsListBean goodsListBean = new GoodsListBean();
			goodsList = goodsListBean.getList(sql);
		 	out.print("--------------"+goodsList.size());
			synchronized(application){
				application.setAttribute("goodsList",goodsList);
			}
		}
		
		application.getRequestDispatcher("/index.jsp").forward(request,response);				
	}

	public void doPost(HttpServletRequest request,HttpServletResponse response)
		throws ServletException,IOException{		
		doGet(request,response);
	}
	
}