使用HttpCore（HttpComponents）在android上构建webService

使用HttpCore可以非常简单的构建HttpServer，HttpCore可以处理Http协议层。

工程里需要引入httpcore.jar，客户端开发需要引入httpclient.jar，下载地址：http://hc.apache.org/downloads.cgi。

服务器端代码如下（get请求返回“<xml><method>get</method><url>&uri</url></xml>"， post请求返回“<xml><method>post</method><url>&uri</url></xml>"）：

package com.mytest.http;


import java.io.File;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.URLDecoder;
import java.nio.charset.Charset;
import java.util.Locale;


import org.apache.http.ConnectionClosedException;
import org.apache.http.HttpEntity;
import org.apache.http.HttpEntityEnclosingRequest;
import org.apache.http.HttpException;
import org.apache.http.HttpRequest;
import org.apache.http.HttpResponse;
import org.apache.http.HttpResponseInterceptor;
import org.apache.http.HttpServerConnection;
import org.apache.http.HttpStatus;
import org.apache.http.MethodNotSupportedException;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.FileEntity;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.DefaultConnectionReuseStrategy;
import org.apache.http.impl.DefaultHttpResponseFactory;
import org.apache.http.impl.DefaultHttpServerConnection;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.CoreConnectionPNames;
import org.apache.http.params.CoreProtocolPNames;
import org.apache.http.params.HttpParams;
import org.apache.http.protocol.BasicHttpContext;
import org.apache.http.protocol.HttpContext;
import org.apache.http.protocol.HttpProcessor;
import org.apache.http.protocol.HttpRequestHandler;
import org.apache.http.protocol.HttpRequestHandlerRegistry;
import org.apache.http.protocol.HttpService;
import org.apache.http.protocol.ImmutableHttpProcessor;
import org.apache.http.protocol.ResponseConnControl;
import org.apache.http.protocol.ResponseContent;
import org.apache.http.protocol.ResponseDate;
import org.apache.http.protocol.ResponseServer;
import org.apache.http.util.EntityUtils;


/**
 * Basic, yet fully functional and spec compliant, HTTP/1.1 file server.
 * <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 file server.
 * 
 * 
 */
public class HttpServer {


	public static void main(String[] args) throws Exception {


		Thread t = new RequestListenerThread(8080);
		t.setDaemon(false);
		t.start();		//start the webservice server
	}




	static class WebServiceHandler implements HttpRequestHandler {


		public WebServiceHandler() {
			super();
		}


		public void handle(final HttpRequest request,
				final HttpResponse response, final HttpContext context)
				throws HttpException, IOException {			


			String method = request.getRequestLine().getMethod()
					.toUpperCase(Locale.ENGLISH);
			//get uri
			String target = request.getRequestLine().getUri();
			if (method.equals("GET") ) {
				response.setStatusCode(HttpStatus.SC_OK);
				StringEntity entity = new StringEntity("<xml><method>get</method><url>" + target + "</url></xml>");
				response.setEntity(entity);
			}
			else if (method.equals("POST") )
			{
				response.setStatusCode(HttpStatus.SC_OK);
				StringEntity entity = new StringEntity("<xml><method>post</method><url>" + target + "</url></xml>");
				response.setEntity(entity);
			}
			else
			{
				throw new MethodNotSupportedException(method
						+ " method not supported");
			}
		}


	}


	static class RequestListenerThread extends Thread {


		private final ServerSocket serversocket;
		private final HttpParams params;
		private final HttpService httpService;


		public RequestListenerThread(int port)
				throws IOException {
			// 
			this.serversocket = new ServerSocket(port);


			// Set up the HTTP protocol processor
			HttpProcessor httpproc = new ImmutableHttpProcessor(
					new HttpResponseInterceptor[] {
							new ResponseDate(), new ResponseServer(),
							new ResponseContent(), new ResponseConnControl() });


			this.params = new BasicHttpParams();
			this.params
					.setIntParameter(CoreConnectionPNames.SO_TIMEOUT, 5000)
					.setIntParameter(CoreConnectionPNames.SOCKET_BUFFER_SIZE,
							8 * 1024)
					.setBooleanParameter(
							CoreConnectionPNames.STALE_CONNECTION_CHECK, false)
					.setBooleanParameter(CoreConnectionPNames.TCP_NODELAY, true)
					.setParameter(CoreProtocolPNames.ORIGIN_SERVER,
							"HttpComponents/1.1");


			// Set up request handlers
			HttpRequestHandlerRegistry reqistry = new HttpRequestHandlerRegistry();
			reqistry.register("*", new WebServiceHandler());  //WebServiceHandler用来处理webservice请求。


			this.httpService = new HttpService(httpproc,
					new DefaultConnectionReuseStrategy(),
					new DefaultHttpResponseFactory());
			httpService.setParams(this.params);
			httpService.setHandlerResolver(reqistry);		//为http服务设置注册好的请求处理器。


		}


		@Override
		public void run() {
			System.out.println("Listening on port "
					+ this.serversocket.getLocalPort());
			System.out.println("Thread.interrupted = " + Thread.interrupted()); 
			while (!Thread.interrupted()) {
				try {
					// Set up HTTP connection
					Socket socket = this.serversocket.accept();
					DefaultHttpServerConnection conn = new DefaultHttpServerConnection();
					System.out.println("Incoming connection from "
							+ socket.getInetAddress());
					conn.bind(socket, this.params);


					// Start worker thread
					Thread t = new WorkerThread(this.httpService, conn);
					t.setDaemon(true);
					t.start();
				} catch (InterruptedIOException ex) {
					break;
				} catch (IOException e) {
					System.err
							.println("I/O error initialising connection thread: "
									+ e.getMessage());
					break;
				}
			}
		}
	}


	static class WorkerThread extends Thread {


		private final HttpService httpservice;
		private final HttpServerConnection conn;


		public WorkerThread(final HttpService httpservice,
				final HttpServerConnection conn) {
			super();
			this.httpservice = httpservice;
			this.conn = conn;
		}


		@Override
		public void run() {
			System.out.println("New connection thread");
			HttpContext context = new BasicHttpContext(null);
			try {
				while (!Thread.interrupted() && this.conn.isOpen()) {
					this.httpservice.handleRequest(this.conn, context);
				}
			} catch (ConnectionClosedException ex) {
				System.err.println("Client closed connection");
			} catch (IOException ex) {
				System.err.println("I/O error: " + ex.getMessage());
			} catch (HttpException ex) {
				System.err.println("Unrecoverable HTTP protocol violation: "
						+ ex.getMessage());
			} finally {
				try {
					this.conn.shutdown();
				} catch (IOException ignore) {
				}
			}
		}
	}
}

客户端代码如下（注意，在android 3.0及其后版本中，此端代码不能在main主线程里工作，否则会报网络异常导致退出）：

		DefaultHttpClient client = new DefaultHttpClient();

		HttpGet httpGet = new HttpGet(”http://localhost:8080/“);
		HttpResponse httpResponse = client.execute(httpGet);
		if (httpResponse.getStatusLine().getStatusCode() == 200) {
			response = EntityUtils.toString(httpResponse.getEntity());
		}