Jsp+Servlet实现购物车功能

本文实例为大家分享了Servlet实现购物车功能的具体代码，供大家参考，具体内容如下

(1)用servlet实现简单的购物车系统，项目结构例如以下：（新建web Project项目  仅仅须要AddItemServlet ， ListItemServlet。exam403.jsp三个文件就可以。其它的不用管）

（2）exam403.jsp代码例如以下：

<%@ page contentType="text/html; charset=gb2312" language="java" import="java.sql.*" errorPage="" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>
</head>

<body>
<form id="form1" name="form1" method="post" action="/servletProject/addItem">
 <label></label>
 商品:
 <select name="itemID" id="itemID">
  <option value="洗衣粉">洗衣粉</option>
  <option value="香皂">香皂</option>
  <option value="食用油">食用油</option>
 </select>
 <p>数量:
  <label>
  <input name="quantity" type="text" id="quantity" value="1" />
  </label>
  <label>
  <input type="submit" name="Submit" value="提交" />
  </label>
  <a href="/servletProject/listItem">查看购物车</a></p>
</form>
</body>
</html>

（3）AddItemServlet代码例如以下：

package com.lc.shoppingCar;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
public class AddItemServlet extends HttpServlet
{
 protected void doGet(HttpServletRequest request,HttpServletResponse response)
             throws ServletException,java.io.IOException
  {
   ServletContext application=getServletContext() ;
   ServletConfig config=getServletConfig() ;
   response.setContentType("text/html;charset=gb2312");
   PrintWriter out=response.getWriter();
   HttpSession session =request.getSession();
   request.setCharacterEncoding("gb2312");

   //读取表单传入的商品ID及数量
   String id=request.getParameter("itemID");
 String num=request.getParameter("quantity");
 if(id!=null && num.length()!=0)
 { //从Sessionn中读取购物车
 HashMap shoppingCar=(HashMap)session.getAttribute("shoppingCar");
   if(shoppingCar==null)
    shoppingCar=new HashMap();
   //将商品加入到购物车中
   String onum=(String)shoppingCar.get(id);
   if(onum==null)
     shoppingCar.put(id,num);
   else
   {
    int n1=Integer.parseInt(num);
   int n2=Integer.parseInt(onum);
   String result=String.valueOf(n1+n2);
   shoppingCar.put(id,result);
   }
     //将购物车写回session中保存
   session.setAttribute("shoppingCar",shoppingCar);
  }
  else //假设传入的商品ID号为空或数量为空。显示提示信息
   System.out.print("商品ID号为空会或数量为空！");
  //返回商品列表页
  response.sendRedirect("/servletProject/exam403.jsp");
   } 

protected void doPost(HttpServletRequest request,HttpServletResponse response)
                throws ServletException,java.io.IOException
 {
   doGet(request,response);
  }
}

（4）ListItemServlet代码例如以下：

package com.lc.shoppingCar;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
public class ListItemServlet extends HttpServlet
{
 protected void doGet(HttpServletRequest request,HttpServletResponse response)
             throws ServletException,java.io.IOException
  {
   ServletContext application=getServletContext() ;
   ServletConfig config=getServletConfig() ;
   response.setContentType("text/html;charset=gb2312");
   PrintWriter out=response.getWriter();
   HttpSession session =request.getSession();
   request.setCharacterEncoding("gb2312");

    //从session中获取购物车
 HashMap shoppingCar=(HashMap)session.getAttribute("shoppingCar");
  //显示购物车中的内容
  if(shoppingCar!=null)
  {
    Set show=shoppingCar.entrySet();
    Iterator it=show.iterator();
    while(it.hasNext())
    {
     out.print(it.next()+"<br>");
    }
  }
  else
    out.print("购物车为空。");
   } 

protected void doPost(HttpServletRequest request,HttpServletResponse response)
                throws ServletException,java.io.IOException
 {
   doGet(request,response);
  }
}

（5）实现效果例如以下：

訪问：http://localhost:8080/servletProject/exam403.jsp    学则商品 提交

点击查看购物车：

OK！

简单的购物车 到此结束！

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