Java tutorial
/* * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. * * Copyright (c) 2012 Oracle and/or its affiliates. All rights reserved. * * The contents of this file are subject to the terms of either the GNU * General Public License Version 2 only ("GPL") or the Common Development * and Distribution License("CDDL") (collectively, the "License"). You * may not use this file except in compliance with the License. You can * obtain a copy of the License at * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html * or packager/legal/LICENSE.txt. 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However, if you add GPL Version 2 code * and therefore, elected the GPL Version 2 license, then the option applies * only if the new code is made subject to such option by the copyright * holder. */ package org.sample.asyncclient; import java.io.IOException; import java.io.PrintWriter; import java.util.concurrent.ExecutionException; import java.util.concurrent.Future; import java.util.logging.Level; import java.util.logging.Logger; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.ws.rs.client.Client; import javax.ws.rs.client.ClientBuilder; import javax.ws.rs.client.InvocationCallback; import javax.ws.rs.client.WebTarget; import javax.ws.rs.core.Response; /** * @author Arun Gupta */ @WebServlet(name = "TestServlet", urlPatterns = { "/TestServlet" }) public class TestServlet extends HttpServlet { /** * Processes requests for both HTTP * <code>GET</code> and * <code>POST</code> methods. * * @param request servlet request * @param response servlet response * @throws ServletException if a servlet-specific error occurs * @throws IOException if an I/O error occurs */ protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { try { final PrintWriter out = response.getWriter(); response.setContentType("text/html;charset=UTF-8"); out.println("<html>"); out.println("<head>"); out.println("<title>Servlet TestServlet</title>"); out.println("</head>"); out.println("<body>"); out.println("<h1>JAX-RS 2 Async Client</h1>"); Client client = ClientBuilder.newClient(); WebTarget target = client.target("http://localhost:8080/filter/webresources/fruits"); // Polling (Response) out.println("Invoking Future<Response>..."); Future<Response> r1 = target.request().async().get(); out.println("<br>Received response (Future<Response>): " + r1.get().readEntity(String.class)); // Polling (String) out.println("<br>Invoking Future<String>..."); Future<String> r2 = target.request().async().get(String.class); out.println("<br>Received response (Future<String>): " + r2.get()); // Polling (String) out.println("<br>Invoking Future<String>..."); Future<String> r3 = target.request().async().get(String.class); out.println("<br>Received response (Future<String>): " + r3.get()); // Callback out.println("<br>Invoking InvocationCallback<String>..."); target.request().async().get(new InvocationCallback<String>() { @Override public void completed(String r) { System.out.println("Received response (InovcationCallback<String>): " + r); } @Override public void failed(Throwable t) { t.printStackTrace(out); } }); out.print("<br>Check server.log for InvocationCallback<String> results."); out.println("</body>"); out.println("</html>"); } catch (InterruptedException | ExecutionException ex) { Logger.getLogger(TestServlet.class.getName()).log(Level.SEVERE, null, ex); } } // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code."> /** * Handles the HTTP * <code>GET</code> method. * * @param request servlet request * @param response servlet response * @throws ServletException if a servlet-specific error occurs * @throws IOException if an I/O error occurs */ @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); } /** * Handles the HTTP * <code>POST</code> method. * * @param request servlet request * @param response servlet response * @throws ServletException if a servlet-specific error occurs * @throws IOException if an I/O error occurs */ @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); } /** * Returns a short description of the servlet. * * @return a String containing servlet description */ @Override public String getServletInfo() { return "Short description"; }// </editor-fold> }