|
Mahesh and others,
After performing the test myself and looking
at things, I found out that indeed the dispatch servlet is putting the bean in
correctly and the jsps are utilizing them properly. The problem
occurs only after I compile any file used by the Bean. Although the Bean
isn't compiled itself (the .class file remains the same); the compilation of a
class imported by the bean causes the ClassCastException. Only after
restarting tomcat do things function properly until the next compilation of the
file used by the Bean.
As a result, I transfer the focus of this problem
away from the jsp realm to the Java language realm. Does anyone have any
idea why the compilation of imported classes would cause a ClassCastException as
previously described?
Thanks again!
Leon
----- Original Message -----
Sent: Friday, May 25, 2001 9:56 AM
Subject: Re: (EXPERTS ONLY) Bean Creation
in Dispatch Servlet
Darn it all!
The jsp should look like this. I forgot to
take my own class name out of a few lines.
<%try{
System.out.println((request.getAttribute("thebean") ==
null));
System.out.println((request.getAttribute("thebean") instanceof
com.blah.blah.AnyCustomBean));
System.out.println((request.getAttribute("thebean").getClass().getName()));
System.out.println((com.blah.blah.AnyCustomBean)request.getAttribute("thebean"));
}catch (ClassCastException e){
System.out.println("CLASS CAST EXCEPTION!");
}
%>
----- Original Message -----
Sent: Friday, May 25, 2001 9:53
AM
Subject: Re: (EXPERTS ONLY) Bean
Creation in Dispatch Servlet
Mahesh,
One more thing, in the servlet the
line...
thebean =
(com.blah.blah.AnyCustomBean)
Beans.instantiate(this.getClass().getClassLoader(),
"com.blah.blah.AnyCustomBean");
...needs to have a try/catch block around it
for a ClassNotFoundException.
Leon
----- Original Message -----
Sent: Friday, May 25, 2001
9:48 AM
Subject: Re: (EXPERTS ONLY)
Bean Creation in Dispatch Servlet
Here is a very scaled down version of the
dispatch servlet. Switch the name of the bean
('com.blah.blah.AnyCustomBean') in the jsp and servlet to any custom bean
you wish to try out.
Create a .jsp page for the servlet to
forward the request to that looks something like
this:
<%@ page session="false"
errorPage="error.jsp" %>
<%@ page import =
"com.blah.blah.AnyCustomBean" %>
<%try{
System.out.println((request.getAttribute("thebean") ==
null));
System.out.println((request.getAttribute("thebean") instanceof
zedak.docworx.jspsupport.beans.BrandBean));
System.out.println((request.getAttribute("thebean").getClass().getName()));
System.out.println((zedak.docworx.jspsupport.beans.BrandBean)request.getAttribute("thebean"));
}catch (ClassCastException e){
System.out.println("CLASS CAST EXCEPTION!");
}
%>
<jsp:useBean id="thebean" scope="request"
class="com.blah.blah.AnyCustomBean" />
Change the name of the jsp file in the
servlet to match the .jsp file name you created above.
Thanks!
Leon
----- Original Message -----
Sent: Friday, May 25, 2001
9:20 AM
Subject: RE: (EXPERTS
ONLY) Bean Creation in Dispatch Servlet
Can you
send the example code ?
Yes, but I need to cast it to
use the Bean specific functionality and...
(com.blah.blah.MyBean)request.getAttribute("thename");
...causes the ClassCastException to
occur.
----- Original Message -----
Sent: Friday, May 25,
2001 9:11 AM
Subject: RE: (EXPERTS
ONLY) Bean Creation in Dispatch Servlet
Hi
Have
you tried the simple way of :
com.blah.blah.MyBean abean = new
com.blah.blah.MyBean();
request.setAttribute("thename",
abean);
in JSP :
com.blah.blah.MyBean abean =
request.getAttribute("thename");
regards
mahesh
Hello All,
Let me preface this email by saying
that I only put 'EXPERTS ONLY' so you hot shot programmers would
actually read this email. If you are reading this, it
worked!
I have an odd problem that I was
hoping someone could help with.
I have a servlet that all jsps in the
system are dispatched from. I create a bean in this servlet
and add it to the request object like so...
com.blah.blah.MyBean abean = (com.blah.blah.MyBean)
Beans.instantiate(this.getClass().getClassLoader(),"com.blah.blah.MyBean");
...
request.setAttribute("thename",
abean);
I have also tried this to create the
bean....
com.blah.blah.MyBean abean = new
com.blah.blah.MyBean();
and also tried to place the object in the request like
so....
pageContext.setAttribute("thename", abean,
PageContext.REQUEST_SCOPE);
Anywho, I then have the following in
my jsp page...
<jsp:useBean
id="thename" scope="request" class="com.blah.blah.MyBean"
/>
I get a java.lang.ClassCastException
from the jsp. So, I decided to do a little error hunting
in a jsp using the following code...
<%try{
System.out.println(request.getAttribute("thename") ==
null);
System.out.println(request.getAttribute("thename") instanceof
com.blah.blah.MyBean);
System.out.println(request.getAttribute("thename").getClass().getName());
System.out.println(zedak.docworx.jspsupport.beans.BrandBean)request.getAttribute("thename"));
}catch (ClassCastException
e){
System.out.println("CLASS CAST
EXCEPTION!");
}
%>
The results of the code is as
follows:
false
false
com.blah.blah.MyBean
CLASS CAST
EXCEPTION!
So, the attribute is present in the
request object, it is not an instance of 'com.blah.blah.MyBean';
but the object's class name is 'com.blah.blah.MyBean'. Does
anyone have an idea what is going on? How can the
object's class name be 'com.blah.blah.MyBean' but not be able to
cast to 'com.blah.blah.MyBean'?
Thanks in advance!
Leon
Palermo
Important:
Internet communications are not
necessarily secure and may be intercepted or changed after they are
sent.
The Abbey National Group does not accept liability for any
such changes. If you wish to confirm the origin or content of this
communication, please contact the sender using an alternative means
of communication.
This communication does not create or
modify any contract.
If you are not the intended recipient of
this communication you should destroy it without copying, disclosing
or otherwise using its contents. Please notify the sender
immediately of the error.
The Abbey National Group comprises
Abbey National plc and its subsidiary group of
companies.
Abbey National plc. Registered Office: Abbey
House, Baker Street, London, NW1 6XL. Reg. No.
2294747.
Registered in
England.
|
