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From "Richard J. Duncan" <RDun...@bds.com>
Subject RE: No Error Message But A Blank Page Is Displayed.
Date Tue, 30 Sep 2003 17:08:31 GMT
In my experience, this is because your execute/perform is returning null as the result of findForward("forwardname")
not finding anything. Usually, this is because I misspelled the forward name.

Returning null from execute/perform tells struts that your method wrote the response itself.

Regards,
 
Rich

-----Original Message-----
From: amind@nc.com.my [mailto:amind@nc.com.my] 
Sent: Tuesday, September 30, 2003 3:05 AM
To: Struts Users Mailing List
Subject: Re: No Error Message But A Blank Page Is Displayed.

Your missing html:form
> My welcome page "is displayed" as the very first
> screen without any problem.  The page has
> <logic:present> and <logic:notPresent> tags, which
> test if any registered user has logged on.
>
> The problem occurred after I filled out username, and
> clicked the "Submit" button.  Thereafter, the welcome
> page was not shown.  My welcome page looks like the
> following:
>
> Welcome.jsp
>
> <%@ taglib uri="/tags/struts-bean" prefix="bean" %>
> <%@ taglib uri="/tags/struts-html" prefix="html" %>
> <%@ taglib uri="/tags/struts-logic" prefix="logic" %>
> <HTML>
> <HEAD>
> <TITLE>Welcome!</TITLE>
> <html:base/>
> </HEAD>
> <BODY>
> <logic:present name="user">
> <H3>Welcome <bean:write name="user"
> property="username"/>!</H3>
> </logic:present>
> <logic:notPresent scope="session" name="user">
> <H3>Welcome World!</H3>
> </logic:notPresent>
> <html:errors/>
> <UL>
> <LI><html:link forward="logon">Sign
> in</html:link></LI>
> <logic:present name="user">
> <LI><html:link forward="logoff">Sign
> out</html:link></LI>
> </logic:present>
> </UL>
> <IMG src='struts-power.gif' alt='Powered by Struts'>
> </BODY>
> </HTML>
> --- Kwok Peng Tuck <pengtuck@makmal.net> wrote:
>> You might want to put System.out.println("Line
>> [number]") ; to see
>> the flow in your action. BTW did you actually put
>> anything(like hello
>> world) in Welcome.jsp ?
>>
>>
>> Caroline Jen wrote:
>>
>> >Which resource file needs to be updated?  I have
>> >checked the application.properties.  Nothing in
>> that
>> >file is relevant to my problem.
>> >--- Abhijeet Mahalkar
>> ><Abhijeet.Mahalkar@indussoft.com> wrote:
>> >
>> >
>> >>have u updated the Resource files... ?
>> >>abhijeet
>> >>
>> >>----- Original Message -----
>> >>From: "Caroline Jen" <jiapei_jen@yahoo.com>
>> >>To: <struts-user@jakarta.apache.org>
>> >>Sent: Tuesday, September 30, 2003 9:45 AM
>> >>Subject: No Error Message But A Blank Page Is
>> >>Displayed.
>> >>
>> >>
>> >>I am experimenting a basic application - logon.  I
>> >>got
>> >>the first two screens working without problem.
>> >>However, the third screen displays a blank page
>> (no
>> >>error message).  I am having a very difficult time
>> >>to
>> >>figure out the problem; henceforth, seeking help.
>> >>Here is the history of my application:
>> >>
>> >>1. http://localhost:8080/LogonPractice/index.jsp
>> (no
>> >>problem and I clicked on "Sign in")
>> >>2.
>> >>
>> >>
>> >>
>>
>>http://localhost:8080/LogonPractice/Logon.do;jsessionid=170B50E4D8E07EE36290E98342E8BF9C
>> >
>> >
>> >>(no problem and the screen asked for username and
>> >>password.  I filled out the information and
>> clicked
>> >>on
>> >>"Submit")
>> >>3.
>> >>http://localhost:8080/LogonPractice/LogonSubmit.do
>> >>(displayed a blank page)
>> >>
>> >>The Tomcat log file shows the following (no error
>> >>message at all):
>> >>
>> >>2003-09-29 23:29:26 action: Processing a GET for
>> >>/Logon
>> >>2003-09-29 23:29:26 action:  Looking for Action
>> >>instance for class
>> >>org.apache.struts.actions.ForwardAction
>> >>2003-09-29 23:29:26 action:   Double checking for
>> >>Action instance already there
>> >>2003-09-29 23:29:26 action:   Creating new Action
>> >>instance
>> >>2003-09-29 23:29:35 action: Processing a POST for
>> >>/LogonSubmit
>> >>2003-09-29 23:29:35 action:  Looking for
>> ActionForm
>> >>bean under attribute 'logonForm'
>> >>2003-09-29 23:29:35 action:  Creating new
>> ActionForm
>> >>instance of class
>> >>'org.apache.artimus.logon.LogonForm'
>> >>2003-09-29 23:29:35 action:  Storing instance
>> under
>> >>attribute 'logonForm' in scope 'request'
>> >>2003-09-29 23:29:35 action:  Populating bean
>> >>properties from this request
>> >>2003-09-29 23:29:35 action:  Validating input form
>> >>properties
>> >>2003-09-29 23:29:35 action:   No errors detected,
>> >>accepting input
>> >>2003-09-29 23:29:35 action:  Looking for Action
>> >>instance for class
>> >>org.apache.artimus.logon.LogonAction
>> >>2003-09-29 23:29:35 action:   Double checking for
>> >>Action instance already there
>> >>2003-09-29 23:29:35 action:   Creating new Action
>> >>instance
>> >>
>> >>in my struts-config.xml, I have:
>> >>
>> >>        <action
>> >>            path="/LogonSubmit"
>> >>
>> >>type="org.apache.artimus.logon.LogonAction"
>> >>            name="logonForm"
>> >>            scope="request"
>> >>            validate="true"
>> >>            input="/signin/Logon.jsp">
>> >>            <forward
>> >>                name="valid"
>> >>                path="/signin/Welcome.jsp"/>
>> >>        </action>
>> >>
>> >>and my LogonAction.java is:
>> >>
>> >>package org.apache.artimus.logon;
>> >>
>> >>import java.io.IOException;
>> >>import javax.servlet.ServletException;
>> >>import javax.servlet.http.HttpServletRequest;
>> >>import javax.servlet.http.HttpSession;
>> >>import javax.servlet.http.HttpServletResponse;
>> >>import org.apache.struts.action.Action;
>> >>import org.apache.struts.action.ActionError;
>> >>import org.apache.struts.action.ActionErrors;
>> >>import org.apache.struts.action.ActionForm;
>> >>import org.apache.struts.action.ActionForward;
>> >>import org.apache.struts.action.ActionMapping;
>> >>import org.apache.struts.action.ActionServlet;
>> >>
>> >>import org.apache.artimus.lang.Constants;
>> >>
>> >>public final class LogonAction extends Action {
>> >>
>> >>    public boolean isUserLogon(String username,
>> >>        String password) throws
>> >>UserDirectoryException
>> >>{
>> >>
>> >>        return
>> >>
>> >>
>> >>
>>
>>(UserDirectory.getInstance().isValidPassword(username,password));
>> >
>> >
>> >>        // return true;
>> >>
>> >>    }
>> >>
>> >>
>> >>    public ActionForward execute(ActionMapping
>> >>mapping,
>> >>            ActionForm form,
>> >>            HttpServletRequest request,
>> >>            HttpServletResponse response)
>> >>        throws IOException, ServletException {
>> >>
>> >>        // Obtain username and password from web
>> >>tier
>> >>        String username = ((LogonForm)
>> >>form).getUsername();
>> >>        String password = ((LogonForm)
>> >>form).getPassword();
>> >>
>> >>        // Validate credentials with business tier
>> >>        boolean validated = false;
>> >>        try {
>> >>
>> >>            validated =
>> >>isUserLogon(username,password);
>> >>        }
>> >>
>> >>        catch (UserDirectoryException ude) {
>> >>            // couldn't connect to user directory
>> >>            ActionErrors errors = new
>> >>ActionErrors();
>> >>            errors.add(ActionErrors.GLOBAL_ERROR,
>> >>            new
>> ActionError("error.logon.connect"));
>> >>            saveErrors(request,errors);
>> >>            // return to input page
>> >>            return (new
>> >>ActionForward(mapping.getInput()));
>> >>        }
>> >>
>> >>        if (!validated) {
>> >>            // credentials don't match
>> >>            ActionErrors errors = new
>> >>ActionErrors();
>> >>            errors.add(ActionErrors.GLOBAL_ERROR,
>> >>            new
>> ActionError("error.logon.invalid"));
>> >>            saveErrors(request,errors);
>> >>            // return to input page
>> >>            return (new
>> >>ActionForward(mapping.getInput()));
>> >>        }
>> >>
>> >>        // Save our logged-in user in the session,
>> >>        // because we use it again later.
>> >>        HttpSession session =
>> request.getSession();
>> >>        session.setAttribute(Constants.USER_KEY,
>>
> === message truncated ===
>
>
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