JSF：无法捕获ViewExpiredException

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问题描述

我正在Glassfish v3上开发一个JSF 2.0应用程序，我正在尝试处理ViewExpiredException。但无论我做什么，我总是得到一个Glassfish错误报告，而不是我自己的错误页面。

I'm developing a JSF 2.0 application on Glassfish v3 and i'm trying to handle the ViewExpiredException. But whatever i do, i always get a Glassfish error report instead of my own error page.

为了模拟VEE的发生，我将以下函数插入到我的支持中发射VEE的豆子。我通过commandLink从我的JSF页面触发此函数。
代码：

To simulate the occurrence of the VEE, i inserted the following function into my backing bean, which fires the VEE. I'm triggering this function from my JSF page through a commandLink.The Code:

@Named
public class PersonHome {
  (...)
  public void throwVEE() {
    throw new ViewExpiredException();
  }
}

起初我只是通过添加错误来尝试它页面到我的web.xml：

At first i tried it by simply adding an error-page to my web.xml:

<error-page>
  <exception-type>javax.faces.application.ViewExpiredException</exception-type>
  <location>/error.xhtml</location>
</error-page>

但是这不起作用，我没有重定向到错误，但我看到了Glassfish errorpage，显示带有以下内容的HTTP状态500页面：

But this doesn't work, i'm not redirected to error but i'm shown the Glassfish errorpage, which shows a HTTP Status 500 page with the following content:

description:The server encountered an internal error () that prevented it from fulfilling this request.
exception: javax.servlet.ServletException: javax.faces.application.ViewExpiredException
root cause: javax.faces.el.EvaluationException:javax.faces.application.ViewExpiredException
root cause:javax.faces.application.ViewExpiredException

我接下来尝试编写ExceptionHandlerFactory和CustomExceptionHandler，如 JavaServerFaces 2.0 - 完整参考。所以我将以下标签插入faces-config.xml：

Next thing i tried was to write ExceptionHandlerFactory and a CustomExceptionHandler, as described in JavaServerFaces 2.0 - The Complete Reference. So i inserted the following tag into faces-config.xml:

<factory>
  <exception-handler-factory>
    exceptions.ExceptionHandlerFactory
  </exception-handler-factory>
</factory>

并添加了这些类：
工厂：

And added these classes:The factory:

package exceptions;

import javax.faces.context.ExceptionHandler;

public class ExceptionHandlerFactory extends javax.faces.context.ExceptionHandlerFactory {

    private javax.faces.context.ExceptionHandlerFactory parent;

    public ExceptionHandlerFactory(javax.faces.context.ExceptionHandlerFactory parent) {
        this.parent = parent;
    }

    @Override
    public ExceptionHandler getExceptionHandler() {
        ExceptionHandler result = parent.getExceptionHandler();
        result = new CustomExceptionHandler(result);
        return result;
    }

}

自定义异常处理程序：

package exceptions;

import java.util.Iterator;

import javax.faces.FacesException;
import javax.faces.application.NavigationHandler;
import javax.faces.application.ViewExpiredException;
import javax.faces.context.ExceptionHandler;
import javax.faces.context.ExceptionHandlerWrapper;
import javax.faces.context.FacesContext;
import javax.faces.event.ExceptionQueuedEvent;
import javax.faces.event.ExceptionQueuedEventContext;

class CustomExceptionHandler extends ExceptionHandlerWrapper {

    private ExceptionHandler parent;

    public CustomExceptionHandler(ExceptionHandler parent) {
        this.parent = parent;
    }

    @Override
    public ExceptionHandler getWrapped() {
        return this.parent;
    }

    @Override
    public void handle() throws FacesException {
        for (Iterator<ExceptionQueuedEvent> i = getUnhandledExceptionQueuedEvents().iterator(); i.hasNext();) {
            ExceptionQueuedEvent event = i.next();
            System.out.println("Iterating over ExceptionQueuedEvents. Current:" + event.toString());
            ExceptionQueuedEventContext context = (ExceptionQueuedEventContext) event.getSource();
            Throwable t = context.getException();
            if (t instanceof ViewExpiredException) {
                ViewExpiredException vee = (ViewExpiredException) t;
                FacesContext fc = FacesContext.getCurrentInstance();

                NavigationHandler nav =
                        fc.getApplication().getNavigationHandler();
                try {
                    // Push some useful stuff to the flash scope for
                    // use in the page
                    fc.getExternalContext().getFlash().put("expiredViewId", vee.getViewId());

                    nav.handleNavigation(fc, null, "/login?faces-redirect=true");
                    fc.renderResponse();

                } finally {
                    i.remove();
                }
            }
        }
        // At this point, the queue will not contain any ViewExpiredEvents.
        // Therefore, let the parent handle them.
        getWrapped().handle();
    }
}

但仍然没有重定向到我的错误页面 - 我收到与上面相同的HTTP 500错误。
我做错了什么，在我的实现中可能缺少哪些异常未正确处理？任何帮助非常感谢！

But STILL i'm NOT redirected to my error page - i'm getting the same HTTP 500 error like above.What am i doing wrong, what could be missing in my implementation that the exception isn't handled correctly? Any help highly appreciated!

编辑

好吧，老实说。事实上，我的代码实际上是用Scala编写的，但这是一个很长的故事。我一直认为这是一个Java问题。
这种情况下的真实错误是我自己的愚蠢。在我的（Scala）代码中，在CustomExceptionHandler中，我忘了添加带有i.remove（）;的行。因此，ViewExpiredException在处理完之后仍保留在UnhandledExceptionsQueue中，并且冒泡。
当它冒泡时，它变成了ServletException。

Ok, i'm honest. In fact, my code is actually written in Scala, but thats a long story. i thought it was a Java problem all the time.The REAL error in this case was my own stupidness. In my (Scala) code, in CustomExceptionHandler, i forgot to add the line with the "i.remove();" So the ViewExpiredException stayed in the UnhandledExceptionsQueue after handling it, and it "bubbled up".And when it bubbles up, it becomes a ServletException.

我真的很抱歉让你们两个都感到困惑！

I'm really sorry for confusing you both!

无法捕获ViewExpiredException

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