update.java

java web开发宝典源代码

package com.yxq.servlet;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import com.yxq.bean.SingleObject;

public class Update extends HttpServlet {
	private Map havemap=new HashMap();
	protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {
		doPost(request,response);
	}

	protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {
		HttpSession session=request.getSession();
		String sessionID=session.getId();
		Map carmap=(HashMap)session.getAttribute("carmap");
		
		String updateN[]=request.getParameterValues("car_number");
		String updateID[]=request.getParameterValues("car_id");
		if((updateN==null||updateN.length==0)||(updateID==null||updateID.length==0)||(carmap==null||carmap.size()==0)){}
		else{
			for(int i=0;i<carmap.size();i++){
				int num=0;
				try{
					num=Integer.parseInt(updateN[i]); 
				}catch(Exception e){
					num=1;
				}
				if(num<0)
					num=1;
				SingleObject carsingle=(SingleObject)carmap.get(Integer.valueOf(updateID[i]));
				carsingle.setMessage("");
				if(num==carsingle.getBuyN()){
					continue;
				}
				else{
					int exist=0;
					havemap=(HashMap)session.getServletContext().getAttribute("havemap");
					if(havemap!=null&&havemap.size()!=0&&havemap.containsKey(Integer.valueOf(updateID[i]))){
						synchronized(havemap){						
							exist=(Integer)havemap.get(Integer.valueOf(updateID[i]))-(num-carsingle.getBuyN());
							if(exist<0){
								carsingle.setMessage("库存不足！");					    	  
								carsingle.setHave((Integer)havemap.get(carsingle.getId()));
							}
							else{
								havemap.put(carsingle.getId(),exist);
								session.getServletContext().setAttribute("havemap",havemap);
			         		  
								carsingle.setHave(exist);
								carsingle.setBuyN(num);
								carsingle.setBuyMoney(carsingle.getBuyN()*carsingle.getPrice());
								carmap.put(Integer.valueOf(updateID[i]),carsingle);
							}
						}//synchronized(havemap)
					}		
				}
			}
			session.setAttribute("carmap",carmap);
			
			Map usermap=(HashMap)session.getServletContext().getAttribute("usermap");
			usermap.put(sessionID,carmap);
			session.getServletContext().setAttribute("usermap",usermap);
		}
		RequestDispatcher rd=request.getRequestDispatcher("/templet.jsp");
		rd.forward(request,response);
	}	
}