Problem with shopping cart JSP :( Help :(

[yilmaz <yi...@hwajet.com.tw>]

Hi everyone,
hope i can find a solution from you Gurus.
I wrote a simple shopping cart JSP file that makes use of session attributes and Hastables to store temporary user data. Don't know why, it insists on not to working properly, throwing classCastException : java.util.Vector
at org.apache.jsp._0002fs_0002dcart_0002fshpcart_jsp._jspService(_0002fs_0002dcart_0002fshpcart_jsp.java:71)
	at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:107)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
......
...
I am sure many of you , too, had faced damn this problem.
Although i am not using vectors in my code, i am having exception regarding to Vectors. Can somebody please tell me what is wrong with this before i got crazy , whole afternoon i have been working on this, trying to figure out what the hell problem is. 

Here are some hints for those willing to help me:
win 2000
tomcat 4.0.1
my code :
<%@  page language="java"  import="java.util.*" %>
<%@  page  contentType="text/html; charset=Big5"  %>
<html>

 <head>
  <meta http-equiv="content-type" content="text/html;charset=Big5">
  <title>Shopping cart</title>
 </head>
<%
Hashtable Pnames,Prices,Quantity;
Enumeration items=null;
Integer price=null; int pr=0;
Integer qnt=null; int quant=1;
int total=0;
Integer prodno=null;
String pname="";
Pnames=(Hashtable)session.getAttribute("cart.items");
if (Pnames==null) {
 Pnames = new Hashtable();
Prices=new Hashtable();
 Quantity=new Hashtable();

} else {
Prices=(Hashtable)session.getAttribute("cart.prices");
Quantity=(Hashtable)session.getAttribute("cart.quantity");
}
if (request.getParameter("pname")!=null) {
Pnames.put(new Integer(Integer.parseInt(request.getParameter("prodno"))),request.getParameter("pname"));
Prices.put(new Integer(Integer.parseInt(request.getParameter("prodno"))), new Integer(Integer.parseInt(request.getParameter("price"))));
Quantity.put(new Integer(Integer.parseInt(request.getParameter("prodno"))), new Integer(Integer.parseInt(request.getParameter("qnt"))));
}
session.setAttribute("cart.items",Pnames);
session.setAttribute("cart.prices",Prices);
session.setAttribute("cart.quantity",Quantity);

%>
 <body background="images/bg.jpg">
  <p></p>
 <center><h1>
The items in your Shopping cart:
</h1>
  <p></p>
  <table border="1" cellpadding="0" cellspacing="2" width="466">
   <tr>
    <th>
     <div align="center">
      <b>itemno</b></div>
    </th>
    <th>
     <div align="center">
             <b>item         </b></div>
    </th>
    <th><b>unitprice<br>
      (NT)</b>
     </th>
    <th>
     <div align="center">
       <b>quantity </b></div>
    </th>
    <th>
     <div align="center">
       <b>totalprice<br>
          (NT)</b></div>
    </th>
     <th>
      <div align="center">
       <b>remove</b></div>
     </th>
    </tr>
<%
if ( Pnames.keys()==null){ %>
There are no items in your shopping cart
<% } else {
items= Pnames.keys();
while (items.hasMoreElements()) {
prodno=(Integer)items.nextElement();
pname=(String)Pnames.get(prodno);
price=(Integer)Prices.get(prodno); pr=price.intValue();
qnt=(Integer)Quantity.get(prodno); quant=qnt.intValue();
total+=pr*quant; 
%>
   <tr>
    <td><i><%=prodno.intValue()%></i></td>
    <td><i><%=pname%></i></td>
    <td><i><%=pr%></i></td>
    <td><i><%=qnt%></i></td>
    <td><i><%=quant*pr%></i></td>
     <td>
                                <a href="remove.jsp?prodno=<%=prodno%>"><i>rem</i></a>
     </td>
    </tr>
 <% } // end of while loop%>
  </table>
                <p><b>Total price :</b> <i><%=total%></i>
   <p><% }//end of if loop %></p>
   <table border="1" cellpadding="0" cellspacing="2" width="302">
    <tr>
     <th><a href="checkout.jsp">Check Out</a></th>
     <th><a href="javascript:history.go(-1)">Go to Previous Page</a></th>
     <th><a href="remove.jsp">Empty Shopping Cart</a></th>
    </tr>
   </table>
   <p></p>
  </center>

 </body>
</html>

Re: Problem with shopping cart JSP :( Help :(

[David Rault <to...@free.fr>]

hi

the ClassCastException _only_ occurs when _you_ try to cast an object to a
type it does not belong to

so i guess you have to check that all your
"Pnames=(Hashtable)session.getAttribute("cart.items");"
refer to object that _really_ are hashtables (they may even be null, that's
no problem)
where do you put them in your user's session ?
and how ?

----- Original Message -----
From: "yilmaz" <yi...@hwajet.com.tw>
To: "Tomcat Users List" <to...@jakarta.apache.org>
Sent: Friday, April 12, 2002 9:37 AM
Subject: Problem with shopping cart JSP :( Help :(


Hi everyone,
hope i can find a solution from you Gurus.
I wrote a simple shopping cart JSP file that makes use of session attributes
and Hastables to store temporary user data. Don't know why, it insists on
not to working properly, throwing classCastException : java.util.Vector
at
org.apache.jsp._0002fs_0002dcart_0002fshpcart_jsp._jspService(_0002fs_0002dc
art_0002fshpcart_jsp.java:71)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:107)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
......




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