AppModule.java

public static void contributeServiceOverride(            MappedConfiguration
     
      , Object> configuration,            @Local RequestExceptionHandler handler)    {        configuration.add(RequestExceptionHandler.class, handler);    }        public RequestExceptionHandler buildRequestExceptionHandler2(final ResponseRenderer renderer,            final ComponentSource componentSource)    {        return new RequestExceptionHandler() {            public void handleRequestException(Throwable exception) throws IOException            {                ExceptionReporter errorPage = (ExceptionReporter) componentSource.getPage("ErrorReporter");                errorPage.reportException(exception);                renderer.renderPageMarkupResponse("ErrorReporter");            }        };    }
     

ErrorReporter.java

public class ErrorReporter implements ExceptionReporter{    @Property    private String errorMessage;    public void reportException(Throwable exception)    {        errorMessage = exception.getMessage();    }}

基本就是上面的样子了。。。