Newbie Problem with Exception handling and pages.xml

[sheadley3228]

I am new with seam and require a little bit of guidance. I am trying to handle application wide exceptions through the use of pages.xml and the <exception class> tags. If I forceably thow an exception in my application for testing purpose, with the following tag in my pages.xml:


<end-conversation/>
<redirect view-id="/views/admin/error.xhtml">
Database access failed



I get the following view which is incorrect:

500 Internal Server Error

Servlet error: An exception occurred. The current application deployment descriptors do not allow for including it in this response. Please consult the application log for details.

If I then use the following in my web.xml:

<error-page>
<error-code>500</error-code>
/views/admin/error.xhtml
</error-page>

I get the correct page displayed.

Why is this happenning? How could I maintain one place for all exceptions to be handled which allows all my exception messages to be shown?


My enviornment is OC4J, Seam, RichFaces.

[pmuir]

Do you have seam's debug mode disabled, and facelets development mode turned off?

Try posting with [ code ] tags

[sheadley3228]

Seams like have am now able to transfer to my error.xhtml page, but I have another problem. I don't have access to the xception message or anything dealing with the exception. I have tried 2 approaches:

1. Create an Exception Listener:

import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import javax.faces.event.PhaseEvent;
import javax.faces.event.PhaseId;
import javax.faces.event.PhaseListener;

import org.jboss.seam.annotations.Logger;
import org.jboss.seam.log.Log;
import javax.faces.application.FacesMessage;
import javax.faces.component.UIViewRoot;
import javax.faces.context.ExternalContext;
import javax.faces.context.FacesContext;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ExceptionListener implements PhaseListener{

@Logger private Log log;
static private FacesContext _instance = null;


 static public FacesContext getContext() {
 return _instance;
 }


 public void beforePhase(PhaseEvent event) {
 System.out.println("ExceptionListener BeforePhase: " + event.getPhaseId());
 String viewId = "/document/error.jsp";

 PhaseId phase = event.getPhaseId();
 if (phase == PhaseId.INVOKE_APPLICATION) {

 try {
 set_instance(event.getFacesContext());


 if (getContext() != null && getContext().getExternalContext() != null)
 {
 System.out.println("Analyzing context");
 // Any errors?
 String tracing = getStackTrace();

 System.out.println("trace found "+ tracing);

 // has information so place in message
 if(tracing.length() > 0)
 {
 UIViewRoot view = getContext().getApplication().getViewHandler().
 createView(getContext(), viewId);
 view.setViewId(viewId);
 getContext().setViewRoot(view);
 getContext().renderResponse();
 }
 else
 return;
 }
 }
 catch (Exception ex) {
 log.error(ex.getMessage());
 ex.printStackTrace();
 }
 }
 }

 public void afterPhase(PhaseEvent event) {
 System.out.println("ExceptionListener AfterPhase: " + event.getPhaseId());
 String viewId = "/document/error.jsp";

 PhaseId phase = event.getPhaseId();
 if (phase == PhaseId.INVOKE_APPLICATION) {

 try {
 System.out.println("Setting instance");
 set_instance(event.getFacesContext());
 System.out.println("getContext()");
 if (getContext() != null && getContext().getExternalContext() != null)
 {
 System.out.println("Analyzing context");
 // Any errors?
 String tracing = getStackTrace();

 System.out.println("[[[[trace found "+ tracing +" ]]]]");

 // has information so place in message
 if(tracing.length() > 0)
 {
 UIViewRoot view = getContext().getApplication().getViewHandler().
 createView(getContext(), viewId);
 view.setViewId(viewId);
 getContext().setViewRoot(view);
 getContext().renderResponse();
 }
 else
 return;
 }
 }
 catch (Exception ex) {
 log.error(ex.getMessage());
 ex.printStackTrace();
 }
 }
 }

 public PhaseId getPhaseId() {
 return PhaseId.INVOKE_APPLICATION;
 }

 public String getStackTrace() {
 System.out.println(">>>>getStackTrace()");
 Object codeObj = null, messageObj = null, typeObj = null;

 System.out.println("Get Request Map");
 ExternalContext xctx = getContext().getExternalContext();
 Object context = xctx.getContext();
 //
 if(context instanceof ServletContext){
 HttpServletRequest request = (HttpServletRequest)getContext().getExternalContext().getRequest();
 codeObj = request.getAttribute("javax.servlet.error.status_code");
 messageObj = request.getAttribute("javax.servlet.error.message");
 typeObj = request.getAttribute("javax.servlet.error.exception_type");
 }

 System.out.println("Get javax.servlet.error.exception");


 return messageObj.toString();

 }

 private void fillStackTrace(Throwable ex, PrintWriter pw) {
 if (null == ex) {
 return;
 }

 ex.printStackTrace(pw);

 if (ex instanceof ServletException) {
 Throwable cause = ((ServletException) ex).getRootCause();

 if (null != cause) {
 pw.println("Root Cause:");
 fillStackTrace(cause, pw);
 }
 } else {
 Throwable cause = ex.getCause();

 if (null != cause) {
 pw.println("Cause:");
 fillStackTrace(cause, pw);
 }
 }
 }


 public static void set_instance(FacesContext _instance) {
 ExceptionListener._instance = _instance;
 }
}

the other method that I used was to create an exception bean:

@Stateful
@Name("errorDisplayBean")
@Scope(ScopeType.APPLICATION)
@Synchronized
@Startup
public class ErrorDisplayBean implements ErrorDisplay{
 public String getStackTrace() {
 System.out.println(">>>>ErrorDisplayBean");
 FacesContext context = FacesContext.getCurrentInstance();
 Map request = context.getExternalContext().getRequestMap();
 Throwable ex = (Throwable) request.get("javax.servlet.error.exception");
 StringWriter sw = new StringWriter();
 PrintWriter pw = new PrintWriter(sw);
 fillStackTrace(ex, pw);
 return sw.toString();
 }

 private static void fillStackTrace(Throwable t, PrintWriter w) {
 if (t == null)
 return;
 t.printStackTrace(w);
 if (t instanceof ServletException) {
 Throwable cause = ((ServletException) t).getRootCause();
 if (cause != null) {
 w.println("Root cause:");
 fillStackTrace(cause, w);
 }
 } else if (t instanceof SQLException) {
 Throwable cause = ((SQLException) t).getNextException();
 if (cause != null) {
 w.println("Next exception:");
 fillStackTrace(cause, w);
 }
 } else {
 Throwable cause = t.getCause();
 if (cause != null) {
 w.println("Cause:");
 fillStackTrace(cause, w);
 }
 }
 }

 @Destroy @Remove
 public void destroy() {}
}

None of these methods returned anything concerning the exception that was thrown. In both cases I had seam debug mode and facelets development turned off.

Thanks for your prompt help

Regards

[pmuir]

There is a bug in Seam with displaying messages from exceptions.

http://jira.jboss.com/jira/browse/JBSEAM-2139