import com.vaadin.server.RequestHandler; //导入依赖的package包/类
@Override
protected List<RequestHandler> createRequestHandlers()
    throws ServiceException {
    List<RequestHandler> handlers = super.createRequestHandlers();
    handlers.add(0, new ServletBootstrapHandler());
    handlers.add(new ServletUIInitHandler());
    if (isAtmosphereAvailable()) {
        handlers.add((RequestHandler) (session, request, response) -> {
            if (!ServletPortletHelper.isPushRequest(request)) {
                return false;
            }
            if (request instanceof VertxVaadinRequest) {
                ((VertxVaadinRequest) request).getRoutingContext().next();
            }
            return true;
        });
    }
    return handlers;
}
 

import com.vaadin.server.RequestHandler; //导入依赖的package包/类
/**
 * initalize a unique RequestHandler
 */
private void initRequestHandler() {
	if (this.requestHandlerUri == null) {
		this.requestHandlerUri = UUID.randomUUID()
				.toString();
		VaadinSession.getCurrent()
				.addRequestHandler(new RequestHandler() {

					@Override
					public boolean handleRequest(final VaadinSession session, final VaadinRequest request, final VaadinResponse response)
							throws IOException {
						if (String.format("/%s", Jcrop.this.requestHandlerUri)
								.equals(request.getPathInfo())) {
							Jcrop.this.resource.getStream()
									.writeResponse(request, response);
							return true;
						} else {
							return false;
						}
					}
				});
	}
}
 

import com.vaadin.server.RequestHandler; //导入依赖的package包/类
@Override
protected void servletInitialized() throws ServletException {
	super.servletInitialized();

          HeaderTagHandler.init(getService());
	
	getService().addSessionInitListener(new SessionInitListener() {

		@Override
		public void sessionInit(SessionInitEvent event) throws ServiceException {
			event.getSession().addRequestHandler(new RequestHandler() {

				@Override
				public boolean handleRequest(VaadinSession session, VaadinRequest request,
						VaadinResponse response) throws IOException {

					String pathInfo = request.getPathInfo();
					InputStream in = null;

					if (pathInfo.endsWith("sw.js")) {
						response.setContentType("application/javascript");
						in = getClass().getResourceAsStream("/sw.js");
					}

					if (in != null) {
						OutputStream out = response.getOutputStream();
						IOUtils.copy(in, out);
						in.close();
						out.close();

						return true;
					} else {

						return false;
					}
				}
			});
		}
	});
}
 

import com.vaadin.server.RequestHandler; //导入依赖的package包/类
/**
  * Creates the parameter handler that will be invoked when the user returns
  * from the OAuth service.
  * 
  * @return the parameter handler
  */
 protected RequestHandler createRequestHandler() {
     return new RequestHandler() {
public boolean handleRequest(VaadinSession session,
		VaadinRequest request, VaadinResponse response)
		throws IOException {
             if (request.getParameterMap().containsKey(getVerifierName())) {
                 String v = request.getParameter(getVerifierName());
                 Verifier verifier = new Verifier(v);
                 accessToken = service
                         .getAccessToken(requestToken, verifier);

                 User user = getUser();

                 VaadinSession.getCurrent().removeRequestHandler(handler);
                 handler = null;
           
                 //String url = getAuthUrl();
                 //callbackPage.open(url, "Authentificate", 400, 300, BorderStyle.DEFAULT);
                 
                 authListener.userAuthenticated(user);

             } else if (getFailureParameters() != null) {
                 for (String key : getFailureParameters()) {
                     if (request.getParameterMap().containsKey(key)) {
                         authListener.failed(request.getParameter(key));
                         break;
                     }
                 }
             }
	return true;
         }
     };
 }