jsp session持久化遇到怪有关问题
日期：2014-05-18 浏览次数：20831 次
jsp session持久化遇到怪问题
问题描述
购物车，新加物品时，修改数量没问题。退出登陆。重新登陆，购物车从数据库读取数据，此时修改数量就出现怪问题，明明我修改1，但是1没变，2变了。
<%@ page language= "java " import= "java.util.* " pageEncoding= "GB18030 "%>
<%@ page import= "com.hotmail.rayyu8.* "%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + ":// "
+ request.getServerName() + ": " + request.getServerPort()
+ path + "/ ";
Object object=session.getAttribute( "usr ");
if(object==null){
response.sendRedirect( "login.jsp ");
}else{
//Collection bookCols = (Collection) session.getAttribute( "books ");
CartBean shopCart = (CartBean) session.getAttribute( "ShopCart ");
//获得参数列表的枚举，如果重新设置过数量的话，枚举便有值
Enumeration paraNames = request.getParameterNames();
//根据枚举，重新设置购物车内商品数量
while (paraNames.hasMoreElements()) {
String bookIdStr = String.valueOf(paraNames.nextElement());
String quantityStr = request.getParameter(bookIdStr);
//request.removeAttribute(bookIdStr);
if (bookIdStr.equals( "submit ")){
break;
}
int bookId = Integer.parseInt(bookIdStr);
int quantity = Integer.parseInt(quantityStr);
shopCart.setItemNum(bookId, quantity);
}
Collection books = shopCart.getItems();
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN ">
<html>
<head>
<base href= " <%=basePath%> ">
<title> 查看购物车 </title>
<meta http-equiv= "pragma " content= "no-cache ">
<meta http-equiv= "cache-control " content= "no-cache ">
<meta http-equiv= "expires " content= "0 ">
<meta http-equiv= "keywords " content= "keyword1,keyword2,keyword3 ">
<meta http-equiv= "description " content= "This is my page ">
<!--
<link rel= "stylesheet " type= "text/css " href= "styles.css ">
-->
</head>
<body> <center>
<P>
<form action= "showcart.jsp " method= "POST ">
<table width= "800px " border= "1 " align= "center ">
<tr>
<td> 书名 </td>
<td> 价格 </td>
<td> 数量 </td>
<td> 小计 </td>
<td> 取消 </td>
</tr>
<%
float total=0.0f;
for (Object obj : books) {
CartItemBean cartItem = (CartItemBean) obj;
BookBean book = cartItem.getBook();
total+=cartItem.getItemPrice();
%>
<tr>
<td>
问题描述
购物车，新加物品时，修改数量没问题。退出登陆。重新登陆，购物车从数据库读取数据，此时修改数量就出现怪问题，明明我修改1，但是1没变，2变了。
<%@ page language= "java " import= "java.util.* " pageEncoding= "GB18030 "%>
<%@ page import= "com.hotmail.rayyu8.* "%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + ":// "
+ request.getServerName() + ": " + request.getServerPort()
+ path + "/ ";
Object object=session.getAttribute( "usr ");
if(object==null){
response.sendRedirect( "login.jsp ");
}else{
//Collection bookCols = (Collection) session.getAttribute( "books ");
CartBean shopCart = (CartBean) session.getAttribute( "ShopCart ");
//获得参数列表的枚举，如果重新设置过数量的话，枚举便有值
Enumeration paraNames = request.getParameterNames();
//根据枚举，重新设置购物车内商品数量
while (paraNames.hasMoreElements()) {
String bookIdStr = String.valueOf(paraNames.nextElement());
String quantityStr = request.getParameter(bookIdStr);
//request.removeAttribute(bookIdStr);
if (bookIdStr.equals( "submit ")){
break;
}
int bookId = Integer.parseInt(bookIdStr);
int quantity = Integer.parseInt(quantityStr);
shopCart.setItemNum(bookId, quantity);
}
Collection books = shopCart.getItems();
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN ">
<html>
<head>
<base href= " <%=basePath%> ">
<title> 查看购物车 </title>
<meta http-equiv= "pragma " content= "no-cache ">
<meta http-equiv= "cache-control " content= "no-cache ">
<meta http-equiv= "expires " content= "0 ">
<meta http-equiv= "keywords " content= "keyword1,keyword2,keyword3 ">
<meta http-equiv= "description " content= "This is my page ">
<!--
<link rel= "stylesheet " type= "text/css " href= "styles.css ">
-->
</head>
<body> <center>
<P>
<form action= "showcart.jsp " method= "POST ">
<table width= "800px " border= "1 " align= "center ">
<tr>
<td> 书名 </td>
<td> 价格 </td>
<td> 数量 </td>
<td> 小计 </td>
<td> 取消 </td>
</tr>
<%
float total=0.0f;
for (Object obj : books) {
CartItemBean cartItem = (CartItemBean) obj;
BookBean book = cartItem.getBook();
total+=cartItem.getItemPrice();
%>
<tr>
<td>
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