Java tutorial
/* * $HeadURL: https://svn.apache.org/repos/asf/httpcomponents/httpcore/tags/4.0.1/httpcore-nio/src/examples/org/apache/http/examples/nio/NHttpClient.java $ * $Revision: 744516 $ * $Date: 2009-02-14 17:38:14 +0100 (Sat, 14 Feb 2009) $ * * ==================================================================== * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * */ import java.io.IOException; import java.io.InterruptedIOException; import java.net.InetSocketAddress; import java.net.URI; import org.apache.http.HttpEntity; import org.apache.http.HttpException; import org.apache.http.HttpHost; import org.apache.http.HttpRequest; import org.apache.http.HttpResponse; import org.apache.http.impl.DefaultConnectionReuseStrategy; import org.apache.http.params.BasicHttpParams; import org.apache.http.impl.nio.DefaultClientIOEventDispatch; import org.apache.http.impl.nio.reactor.DefaultConnectingIOReactor; import org.apache.http.message.BasicHttpRequest; import org.apache.http.nio.NHttpConnection; import org.apache.http.nio.protocol.BufferingHttpClientHandler; import org.apache.http.nio.protocol.EventListener; import org.apache.http.nio.protocol.HttpRequestExecutionHandler; import org.apache.http.nio.reactor.ConnectingIOReactor; import org.apache.http.nio.reactor.IOEventDispatch; import org.apache.http.nio.reactor.SessionRequest; import org.apache.http.nio.reactor.SessionRequestCallback; import org.apache.http.params.CoreConnectionPNames; import org.apache.http.params.HttpParams; import org.apache.http.params.CoreProtocolPNames; import org.apache.http.protocol.BasicHttpProcessor; import org.apache.http.protocol.HttpContext; import org.apache.http.protocol.ExecutionContext; import org.apache.http.protocol.RequestConnControl; import org.apache.http.protocol.RequestContent; import org.apache.http.protocol.RequestExpectContinue; import org.apache.http.protocol.RequestTargetHost; import org.apache.http.protocol.RequestUserAgent; import org.apache.http.util.EntityUtils; /** * Elemental example for executing HTTP requests using the non-blocking I/O model. * <p> * Please note the purpose of this application is demonstrate the usage of HttpCore APIs. * It is NOT intended to demonstrate the most efficient way of building an HTTP client. * * * @version $Revision: 744516 $ */ public class NioHttpClient { ConnectingIOReactor io_reactor; IOEventDispatch io_event_dispatch; public NioHttpClient(String user_agent, HttpRequestExecutionHandler request_handler, EventListener connection_listener) throws Exception { // Construct the long-lived HTTP parameters. HttpParams parameters = new BasicHttpParams(); parameters // Socket data timeout is 5,000 milliseconds (5 seconds). .setIntParameter(CoreConnectionPNames.SO_TIMEOUT, 5000) // Maximum time allowed for connection establishment is 10,00 milliseconds (10 seconds). .setIntParameter(CoreConnectionPNames.CONNECTION_TIMEOUT, 10000) // Socket buffer size is 8 kB. .setIntParameter(CoreConnectionPNames.SOCKET_BUFFER_SIZE, 8 * 1024) // Don't bother to check for stale TCP connections. .setBooleanParameter(CoreConnectionPNames.STALE_CONNECTION_CHECK, false) // Don't use Nagle's algorithm (in other words minimize latency). .setBooleanParameter(CoreConnectionPNames.TCP_NODELAY, true) // Set the user agent string that the client sends to the server. .setParameter(CoreProtocolPNames.USER_AGENT, user_agent); // Construct the core HTTP request processor. BasicHttpProcessor http_processor = new BasicHttpProcessor(); // Add Content-Length header to request where appropriate. http_processor.addInterceptor(new RequestContent()); // Always include Host header in requests. http_processor.addInterceptor(new RequestTargetHost()); // Maintain connection keep-alive by default. http_processor.addInterceptor(new RequestConnControl()); // Include user agent information in each request. http_processor.addInterceptor(new RequestUserAgent()); // Allocate an HTTP client handler. BufferingHttpClientHandler client_handler = new BufferingHttpClientHandler(http_processor, // Basic HTTP Processor. request_handler, new DefaultConnectionReuseStrategy(), parameters); client_handler.setEventListener(connection_listener); // Use two worker threads for the IO reactor. io_reactor = new DefaultConnectingIOReactor(2, parameters); io_event_dispatch = new DefaultClientIOEventDispatch(client_handler, parameters); } public void go() throws Exception { io_reactor.execute(io_event_dispatch); // All exceptions will be propagated to Scheme level. } // Start an HTTP session with endpoint host:port using the given session handler. public SessionRequest openSession(String host, int port, SessionRequestCallback session_handler) { return io_reactor.connect(new InetSocketAddress(host, port), null, new HttpHost(host, port), // HTTP host could be different. Change to accomodate for proxy. session_handler); } // This has no business being here and needs to be put into a class devoted to path and query construction. public static String uriForRequest(URI u) { if (null == u.getQuery()) { return u.getPath(); } else { int n = u.getPath().length() + u.getQuery().length() + 1; StringBuilder b = new StringBuilder(n); b.append(u.getPath()).append('?').append(u.getQuery()); return b.toString(); } } }