import com.vaadin.ui.Upload.FailedListener; //导入依赖的package包/类
private void failedListener()
{
	this.upload.addFailedListener(new FailedListener()
	{
		private static final long serialVersionUID = 1L;

		@Override
		public void uploadFailed(final FailedEvent event)
		{
			UI ui = UI.getCurrent();
			ui.access(() -> {
				Notification
						.show("The upload failed. " + event.getReason() + " Please fix the problem and try again.");
				ImportSelectFile.this.uploadStarted = true;
				ImportSelectFile.this.uploadComplete = false;
			});
		}
	});
}
 

import com.vaadin.ui.Upload.FailedListener; //导入依赖的package包/类
protected void addUpload() {
  this.upload = new Upload(null, receiver);
  upload.setButtonCaption(i18nManager.getMessage(Messages.UPLOAD_SELECT));
  upload.setImmediate(true);
  addComponent(upload);
  setComponentAlignment(upload, Alignment.MIDDLE_CENTER);
  
  // register ourselves as listener for upload events
  upload.addListener((StartedListener) this);
  upload.addListener((FailedListener) this);
  upload.addListener((FinishedListener) this);
  upload.addListener((ProgressListener) this);
}
 

import com.vaadin.ui.Upload.FailedListener; //导入依赖的package包/类
public UploadComponent(String buttonCaption, String sessionId, int maxSize, String folderPath) {
     upload = new Upload();
     this.addComponent(upload);
     this.maxSize = maxSize;
     upload.setReceiver( this); 
     this.directory = folderPath;
     upload.setButtonCaption(buttonCaption);
     upload.addSucceededListener((Upload.SucceededListener) this);
     upload.addFailedListener((Upload.FailedListener) this);
     upload.addProgressListener((Upload.ProgressListener) this);
     upload.addFinishedListener((Upload.FinishedListener) this);
     
     processingLayout = new HorizontalLayout();
     processingLayout.setSpacing(true);
     processingLayout.setVisible(false);
     this.addComponent(processingLayout);

     progressBar = new ProgressBar();
     processingLayout.addComponent(progressBar);
     
     cancelProcessing = new Button("cancel", new Button.ClickListener() {
@Override
public void buttonClick(ClickEvent event) {
	cancelled = true;
             upload.interruptUpload();
	
}
     });
     processingLayout.addComponent(cancelProcessing);
 }
 

import com.vaadin.ui.Upload.FailedListener; //导入依赖的package包/类
public void uploadFailed(FailedEvent event) {
  for (FailedListener failedListener : failedListeners) {
    failedListener.uploadFailed(event);
  }
}
 

import com.vaadin.ui.Upload.FailedListener; //导入依赖的package包/类
public void addFailedListener(FailedListener failedListener) {
  failedListeners.add(failedListener);
}
 

import com.vaadin.ui.Upload.FailedListener; //导入依赖的package包/类
public void addFailedListener(FailedListener failedListener) {
  uploadComponent.addFailedListener(failedListener);
}
 

import com.vaadin.ui.Upload.FailedListener; //导入依赖的package包/类
/**
 * Adds the upload interrupted event listener.
 *
 * @param listener
 *            the Listener to be added, not null
 * @return this for method chaining
 * @see Upload#addFailedListener(FailedListener)
 */
@SuppressWarnings("unchecked")
public default THIS withFailedListener(FailedListener listener) {
    ((Upload) this).addFailedListener(listener);
    return (THIS) this;
}