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Posted to users@tomcat.apache.org by Seth Brahler <sp...@cornell.edu> on 2002/06/27 15:15:36 UTC
URL Variable Error Checking
I'm trying to make an update page as fool-proof as possible, but there is
one error I cannot stop.
At the top of my page I placed this code to incase the user backs off the
url variable. For example, changing the URL
www.mysite.com/update.jsp?ID=4 to www.mysite.com/update.jsp:
<% if(request.getParameter("ID") ==null) {
%>
Stop update
<% } else { %>
Continue Update
<% } %>
However, if I only back off part of the URL variable and change it to
www.mysite.com/update.jsp?ID=, then I get the error:
Syntax error (missing operator) in query expression 'ID =
How can I stop this error? I know in cold fusion there was a Parameter
Exists tag, but I don't know about JSP.
Thank you.
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Re: URL Variable Error Checking
Posted by David Cassidy <da...@twocats.co.uk>.
if a parameter gets passed as ID=
then the value you get is "" ie a zero length string....
So....
Your
if(request.getParameter("ID") ==null)
needs to grow to ...
if(request.getParameter("ID") ==null ||
"".equals(request.getParameter("ID"))
David
Seth Brahler wrote:
> I'm trying to make an update page as fool-proof as possible, but there
> is one error I cannot stop.
>
> At the top of my page I placed this code to incase the user backs off
> the url variable. For example, changing the URL
> www.mysite.com/update.jsp?ID=4 to www.mysite.com/update.jsp:
>
> <% if(request.getParameter("ID") ==null) {
> %>
> Stop update
> <% } else { %>
> Continue Update
> <% } %>
>
> However, if I only back off part of the URL variable and change it to
> www.mysite.com/update.jsp?ID=, then I get the error:
> Syntax error (missing operator) in query expression 'ID =
>
> How can I stop this error? I know in cold fusion there was a Parameter
> Exists tag, but I don't know about JSP.
>
> Thank you.
>
>
>
> --
> To unsubscribe, e-mail:
> <ma...@jakarta.apache.org>
> For additional commands, e-mail:
> <ma...@jakarta.apache.org>
>
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To unsubscribe, e-mail: <ma...@jakarta.apache.org>
For additional commands, e-mail: <ma...@jakarta.apache.org>
Re: URL Variable Error Checking
Posted by Mark O'Driscoll <ma...@eircom.net>.
Try getParameterNames(). This returns a list of parameters. You can then
check if your one is there.
----- Original Message -----
From: "Seth Brahler" <sp...@cornell.edu>
To: <to...@jakarta.apache.org>
Sent: Thursday, June 27, 2002 2:15 PM
Subject: URL Variable Error Checking
> I'm trying to make an update page as fool-proof as possible, but there is
> one error I cannot stop.
>
> At the top of my page I placed this code to incase the user backs off the
> url variable. For example, changing the URL
> www.mysite.com/update.jsp?ID=4 to www.mysite.com/update.jsp:
>
> <% if(request.getParameter("ID") ==null) {
> %>
> Stop update
> <% } else { %>
> Continue Update
> <% } %>
>
> However, if I only back off part of the URL variable and change it to
> www.mysite.com/update.jsp?ID=, then I get the error:
> Syntax error (missing operator) in query expression 'ID =
>
> How can I stop this error? I know in cold fusion there was a Parameter
> Exists tag, but I don't know about JSP.
>
> Thank you.
>
>
>
> --
> To unsubscribe, e-mail:
<ma...@jakarta.apache.org>
> For additional commands, e-mail:
<ma...@jakarta.apache.org>
>
>
--
To unsubscribe, e-mail: <ma...@jakarta.apache.org>
For additional commands, e-mail: <ma...@jakarta.apache.org>