Validation in JSP

Question

Hi,
I am stuck with validation on same jsp page:
Here is the detail:
I have a couple of input fields in form, and if users enter wrong name and id
the validation error will be shown on the same jsp page.
I know there is no problem if using struts validation function.
But for my case, is just simple jsp without other component replying on.
How to achieve this?
Actually the original validation logic is done by jave script
which collected all error message into formated variable,
The popup window for error message display will be shown once users click submit button
Any help?

Answer 1

use another jsp/servlet to do the logic on the
validating then on the
input jsp.it must forward to your input form jsp so
you can repopulate the values of the fields.. you can
have the following codes:
validator.jsp:
//validate here
<%if(success){%>
<jsp:forward page="success.jsp"/>
<%}else{%>
<jsp:forward page="input.jsp?err=error"/>
<%}%>input.jsp
<%
String err =
request.getParameter("err")!=null?request.getParameter
("err"):"none";
String field1 =
request.getParameter("feild1")!=null?request.getParame
ter("feild1"):"";
if(!err.equals("none")){
%>
<%=err%>
<%}%>
<input type="text" value="<%=field1%>"
name="feild1"/>
Raw scriptlet code? When you could and should be using JSTL? Bad idea.
%