why don't you simply validate the user's input before you create the bean
with the validated values. if an error accurs while validation make your
event handler return an error bean with some information about the error,
let your controller check whether this is an error bean or another one, if
it's an error bean call ur error.jsp.
Hope this helps.
-mw
----- Original Message -----
From: "Quinn Stone" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Saturday, June 23, 2001 12:34 AM
Subject: Need guidance on form validation.
> Hi:
>
> I hope someone has come up with an elegant method that solves my
> problem, and is willing to share.
>
> My application is based on the Chapter 6 sample in Wrox "Professional
> JSP 2nd Ed."):
>
> 1. Controller looks up and calls an event handler's process() method.
> 2. The event handler populates one or more beans using JDBC/mySQL and
> stuffs them in session/request as required.
> 3. Controller forwards to jsp, which uses beans to display stuff in a
> form.
>
> Fine so far. Now, the user can update the form fields and click an
> "Update" button, which starts the above steps going again.
>
> If the event handler now finds an error in the user's input, it creates
> an error bean and the controller forwards to the jsp again. I want the
> jsp to display the erroneous input as well as the error messages.
> However, the bean that the jsp is reading from has data types that may
> not accept the user's input. For example, the user might put 15.q0
> (after all, the 'q' is really close to the 'one' key) in a form field
> that is defined as a double in the bean.
>
> I thought, OK, just make the bean properties Strings, and I won't have
> to worry about it. The problem with this is that then I will have to do
> data type conversions whenever I want to use the bean to actually do
> some processing (for example, add the double value to something, do some
> date manipulation, etc.), which makes things, well, ugly.
>
> I suppose I could keep one bean with nothing but String properties
> (string bean?) for display, and another with correct data types, but
> that's ugly, too, unless there's a nice way to accomplish this that I
> haven't thought of.
>
> I really don't want to have two jsp's displaying the same info, or add
> conditions to the jsp causing it to read from the bean or the request
> depending on the situation.
>
> Now that you've waded through all that, any suggestions?
> --
> Quinn Stone
> Stone Consultants
> 2214 1/2 Santa Clara Ave.
> Alameda, CA 94501
> 510.865.7342
> www.stoneconsultants.com
>
>
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