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Posted to user@struts.apache.org by pe...@cibavision.Novartis.com on 2001/01/25 15:23:18 UTC
RE: RE: no 'application' init parameter for ActionServlet causes
NullPoin terException in ??
Martin,
Thanks for the response. That's sort of the same conclusion I came to.
If that's the way it needs to be, that's fine. I like the design of the
resource file. I just skipped it in the interest of getting my first
example working with as little as possible.
Craig & Company: Prehaps it would be possible to modify the documentation
in such a way as to better explain this requirement? I was thrown off by
the description in the javadoc. It would also be cool if the ErrorsTag.java
source checked for a null messages object and threw a more descriptive error
message stating that an application parameter is required, or something.
Just a thought.
Again, thanks for the excellent tool. I'm really excited about using it.
Perry Tew
> -----Original Message-----
> From: Martin Cooper [SMTP:martin.cooper@tumbleweed.com]
> Sent: Wednesday, January 24, 2001 6:54 PM
> To: struts-user@jakarta.apache.org
> Subject: Re: no 'application' init parameter for ActionServlet causes
> NullPoin terException in <struts:errors /> ??
>
> I think the default being specified as [NONE] means:
>
> - If you *do not* use application messages in your code, and do not use
> any
> Struts tags which use them, then you do not need to specify a value for
> 'application' in your configuration.
>
> - If you *do* use application messages directly, or use tags which use
> them,
> then there is no default value and you must specify a valid value.
>
> The <struts:errors/> tag needs to look up messages in the properties file,
> so you will need to specify a value for 'application' in your
> configuration
> if you want to use that tag.
>
> Hope this helps.
>
> --
> Martin Cooper
> Tumbleweed Communications
>
> ----- Original Message -----
> From: <pe...@cibavision.Novartis.com>
> To: <st...@jakarta.apache.org>
> Sent: Wednesday, January 24, 2001 1:10 PM
> Subject: no 'application' init parameter for ActionServlet causes NullPoin
> terException in <struts:errors /> ??
>
>
> > Hello! I'm just beginning to use struts, and I enjoy it very much.
> Thank
> > you to all who have contributed to it. I have encountered a problem and
> > would like to ask about it. I've searched the archives and couldn't
> find
> > anything on this.
> >
> > My problem: When I configure my ActionServlet without specifiying an
> > 'application' init parameter, I receive a NullPointerException when I
> use
> > the <struts:errors /> tag in my jsp page. Has anyone else seen this?
> >
> > The javadoc states the following:
> > The initialization parameters supported by the controller servlet are
> > described below, which is copied from the Javadocs for the ActionServlet
> > class. Square brackets describe the default values that are assumed if
> you
> > do not provide a value for that initialization parameter.
> >
> > application - Java class name of the application resources bundle base
> > class. [NONE]
> > bufferSize - The size of the input buffer used when processing file
> uploads.
> > [4096]
> > config - Context-relative path to the XML resource containing our
> > configuration information. [/WEB-INF/struts-config.xml]
> > ...
> >
> > so, it appears to me that if I don't specify an application parameter, I
> > should be okay. However, I receive the following error:
> >
> > java.lang.NullPointerException at
> > org.apache.struts.taglib.ErrorsTag.doStartTag(ErrorsTag.java:201)
> > at
> >
> _0002flogon_0002ejsplogon_jsp_5._jspService(_0002flogon_0002ejsplogon_jsp_
> 5.
> > java:89)
> > at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:119)
> > at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
> > at
> >
> org.apache.jasper.servlet.JspServlet$JspServletWrapper.service(JspServlet.
> ja
> > va:177)
> > at
> org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:309)
> > at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:382)
> > at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
> > at
> org.apache.tomcat.core.ServletWrapper.doService(ServletWrapper.java:387)
> > at org.apache.tomcat.core.Handler.service(Handler.java:263)
> > at
> org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:371)
> > at
> >
> org.apache.tomcat.facade.RequestDispatcherImpl.forward(RequestDispatcherIm
> pl
> > .java:191)
> > at
> >
> org.apache.struts.action.ActionServlet.processActionForward(ActionServlet.
> ja
> > va:1589)
> > at
> org.apache.struts.action.ActionServlet.process(ActionServlet.java:1432)
> > at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:481)
> > at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
> > at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
> > at
> org.apache.tomcat.core.ServletWrapper.doService(ServletWrapper.java:387)
> > at org.apache.tomcat.core.Handler.service(Handler.java:263)
> > at
> org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:371)
> > at
> >
> org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:
> 74
> > 9)
> > at
> org.apache.tomcat.core.ContextManager.service(ContextManager.java:695)
> > at
> >
> org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(Htt
> pC
> > onnectionHandler.java:207)
> > at
> org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:403)
> >
> > at
> >
> org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:498)
> > at java.lang.Thread.run(Thread.java:484)
> >
> >
> > This is my jsp page:
> > <%@ page errorPage="error.jsp" %>
> > <%@ taglib uri="/WEB-INF/struts.tld" prefix="struts" %>
> > <%@ taglib uri="/WEB-INF/struts-bean.tld" prefix="bean" %>
> > <%@ taglib uri="/WEB-INF/struts-html.tld" prefix="html" %>
> >
> > <html:html locale="true">
> >
> >
> > <head>
> > <!-- BEGIN SCRIPT //-->
> > <script language="JavaScript">
> > <!--
> > function doInit() { document.login_form.username.focus(); }
> > //-->
> > </script>
> > <!-- END SCRIPT //-->
> >
> >
> > <link REL="stylesheet" HREF="/asmt/asmt.css" TYPE="text/css">
> > <title>ASMT Library Login</title>
> > </head>
> >
> >
> >
> > <body onload="doInit()">
> >
> > <struts:errors />
> >
> > <div align="center"><center>
> >
> > <html:form name="login_form" action="logon.do">
> > <div align="center"><center>
> > <table border="0" cellpadding="0" cellspacing="0"
> > width="423">
> > <tr align="center">
> > <td width="423" colspan="3">
> > <center>
> > <h2>ASMT Library System</h2>
> > <h3>Welcome. Please Log In.</h3>
> > </td>
> > </tr>
> >
> > <tr align="center">
> > <td width="107">
> > <div align="left"><p>Username
> > </td>
> > <td width="209" align="left">
> > <div align="left"><p>
> > <html:text property="username" size="20"
> > tabindex="1"/>
> > </td>
> > <td width="107" align="left">
> > <html:submit value="Logon" style="width:
> > 80px" tabindex="4" />
> > </td>
> > </tr>
> >
> > <tr align="center">
> > <td width="107">
> > <div align="left"><p>Password
> > </td>
> > <td width="209" align="left">
> > <html:password property="password" size="20"
> > tabindex="2" />
> > </td>
> > <td width="107" align="left">
> > <html:reset style="width: 80px" tabindex="5"
> > />
> > </td>
> > </tr>
> >
> > </table>
> > </center></div>
> > </html:form>
> >
> > </body>
> > </html:html>
> >
> >
> > Prehaps there's something I'm should be doing in my page that I'm not?
> I've
> > looked at the source code, and the error is because the 'messages'
> object
> is
> > null. It is assigned a few lines above in the following statement:
> > MessageResources messages = (MessageResources)
> > pageContext.getAttribute(Action.MESSAGES_KEY,
> > PageContext.APPLICATION_SCOPE);
> >
> > That's all I know to trace, since I'm new to the code. If I remove the
> > <struts:errors /> tag, the code works fine. I copied the
> > ApplicationResource.properties file, placed it in my classes directory,
> and
> > add the application init parameter and again everything works fine.
> Have
> I
> > done something wrong, is this a bug, or is should the application
> parameter
> > be required for correct operation?
> >
> > Just for completeness, below is my web.xml file and struts-config.xml
> file.
> > My apologies if this is too verbose for some.
> >
> > Thanks for your help,
> > Perry Tew
> >
> > Tomcat 3.2
> > NT4.0 workstation
> > JDK1.3
> >
> >
> __________________________________________________________________________
> __
> > ___________
> > <?xml version="1.0" encoding="ISO-8859-1"?>
> >
> > <!DOCTYPE web-app
> > PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN"
> > "http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">
> >
> > <web-app>
> > <servlet>
> > <servlet-name>libServlet</servlet-name>
> > <servlet-class>ASMTLibraryServlet</servlet-class>
> > </servlet>
> > <servlet-mapping>
> > <servlet-name>libServlet</servlet-name>
> > <url-pattern>/library/*</url-pattern>
> > </servlet-mapping>
> >
> > <!-- Action Servlet Configuration -->
> > <servlet>
> > <servlet-name>action</servlet-name>
> >
> <servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
> > <!--
> > <init-param>
> > <param-name>application</param-name>
> > <param-value>ApplicationResources</param-value>
> > </init-param>
> > -->
> > <init-param>
> > <param-name>config</param-name>
> > <param-value>/WEB-INF/struts-config.xml</param-value>
> > </init-param>
> > <init-param>
> > <param-name>debug</param-name>
> > <param-value>2</param-value>
> > </init-param>
> > <init-param>
> > <param-name>detail</param-name>
> > <param-value>2</param-value>
> > </init-param>
> > <init-param>
> > <param-name>validate</param-name>
> > <param-value>true</param-value>
> > </init-param>
> > <load-on-startup>2</load-on-startup>
> > </servlet>
> >
> > <!-- Action Servlet Mapping -->
> > <servlet-mapping>
> > <servlet-name>action</servlet-name>
> > <url-pattern>*.do</url-pattern>
> > </servlet-mapping>
> >
> >
> > <!-- Struts Tag Library Descriptors -->
> > <taglib>
> > <taglib-uri>/WEB-INF/struts-bean.tld</taglib-uri>
> > <taglib-location>/WEB-INF/struts-bean.tld</taglib-location>
> > </taglib>
> >
> > <taglib>
> > <taglib-uri>/WEB-INF/struts-html.tld</taglib-uri>
> > <taglib-location>/WEB-INF/struts-html.tld</taglib-location>
> > </taglib>
> >
> > <taglib>
> > <taglib-uri>/WEB-INF/struts-logic.tld</taglib-uri>
> > <taglib-location>/WEB-INF/struts-logic.tld</taglib-location>
> > </taglib>
> >
> > </web-app>
> >
> >
> __________________________________________________________________________
> __
> > ___
> > <?xml version="1.0" encoding="ISO-8859-1" ?>
> >
> > <!DOCTYPE struts-config PUBLIC
> > "-//Apache Software Foundation//DTD Struts Configuration
> 1.0//EN"
> > "http://jakarta.apache.org/struts/dtds/struts-config_1_0.dtd">
> >
> > <struts-config>
> > <form-beans>
> > <!-- Logon form bean -->
> > <form-bean name="logonForm"
> > type="LogonForm"/>
> > </form-beans>
> > <global-forwards>
> > <forward name="logon" path="/logon.jsp"/>
> > <forward name="success" path="/main.jsp"/>
> > <forward name="failure" path="/failedLogin.html" />
> > </global-forwards>
> >
> >
> > <action-mappings>
> > <!-- Process a user logon -->
> > <action path="/logon"
> > type="LogonAction"
> > name="logonForm"
> > scope="request"
> > input="/logon.jsp"
> > unknown="true"
> > >
> > </action>
> > </action-mappings>
> > </struts-config>
> >
>
Re: no 'application' init parameter for ActionServlet causes NullPoin
terException in ??
Posted by "Craig R. McClanahan" <Cr...@eng.sun.com>.
perry.tew@cibavision.Novartis.com wrote:
> Martin,
> Thanks for the response. That's sort of the same conclusion I came to.
> If that's the way it needs to be, that's fine. I like the design of the
> resource file. I just skipped it in the interest of getting my first
> example working with as little as possible.
>
> Craig & Company: Prehaps it would be possible to modify the documentation
> in such a way as to better explain this requirement? I was thrown off by
> the description in the javadoc. It would also be cool if the ErrorsTag.java
> source checked for a null messages object and threw a more descriptive error
> message stating that an application parameter is required, or something.
> Just a thought.
>
I've updated the 1.0 version of this tag (<html:errors/>), which you should be
using instead of <struts:errors/> in new development, to display "MISSING
APPLICATION RESOURCES" when this happens. It had appropriate checks for null
values, and would completely ignore the ActionErrors object passed by your
application if there were no resources available.
This will show up in tonight's nightly build.
> Again, thanks for the excellent tool. I'm really excited about using it.
>
> Perry Tew
>
Craig