Thanks Craig.
It works when the two classes are move "learn.jsp" package!
Yep. I have been reading "Web Dev with JSP" book which does explains Java Beans
properly.
--
Peter Pilgrim
G.O.A.T
"The Greatest of All Time"
---------------------------------------- Message History
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From: "Craig R. McClanahan" <[EMAIL PROTECTED]>@java.sun.com> on 17/11/2000
11:04 PST
Please respond to A mailing list about Java Server Pages specification and reference
<[EMAIL PROTECTED]>
DELEGATED - Sent by: A mailing list about Java Server Pages specification and
[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]
cc:
Subject: Re: Developing with Tomcat 3.2beta
Hi Peter, see below:
Peter Pilgrim wrote:
> I am trying to write a mini test MVC with JSP as a test with Tomcat 3.2B
> I wrote two classes :
>
> <WEBAPP>/ROOT/WEB-INF/classes/LocationModel
> <WEBAPP>/ROOT/WEB-INF/classes/LocationController
>
> I am creating a session object in both the JSP and the Servlet with
>
> public class LocationController extends HttpServlet
__<CUT>--
You get a class cast exception because of the way Java treats classes that are not
defined in packages.
When you reference an unpackaged class name from another class, Java assumes that the
other class is in the same package as the one you are compiling. That works fine for
your servlet, because it is correct. However, the generated servlet that is created
for your JSP pages is *not* in the unnamed package -- and,
what's worse, the package it ends up under is different for each servlet container.
The solution is to use a "package" declaration at the top of your two classes (you'll
have to adjust where the .class files go accordingly), and then use fully qualified
class names in the JSP page (or specify the correct import statement). For example,
assume that you put these two classes in a package named
"com.mycompany.mypackage". To make your JSP page work, simply add the following to
the page:
<%@ page import="com.mycompany.mypackage" %>
Of course, you are still working too hard :-). The JSP page will do what your
scriptlet does if you use this approach:
<jsp:useBean id="location_model" scope="session"
class="com.mycompany.mypackage.LocationModel" />
This creates the session scope bean if it's not there already, *and* makes a local
variable named "location_model" available that references this object. The only
"restriction" (if you want to call it that) is that the variable name and the session
attribute key have to be the same, because they are both calculated
from the "id" attribute.
--<CUT>--
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Some relevant FAQs on JSP/Servlets can be found at:
http://java.sun.com/products/jsp/faq.html
http://www.esperanto.org.nz/jsp/jspfaq.html
http://www.jguru.com/jguru/faq/faqpage.jsp?name=JSP
http://www.jguru.com/jguru/faq/faqpage.jsp?name=Servlets
