operatorconnectproxy.java

用java调用httpclient的方式获取网页内容

/*
 * $HeadURL: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk/module-client/src/examples/org/apache/http/examples/conn/OperatorConnectProxy.java $
 * $Revision: 645850 $
 * $Date: 2008-04-08 13:08:52 +0200 (Tue, 08 Apr 2008) $
 *
 * ====================================================================
 * 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/>.
 *
 */

package org.apache.http.examples.conn;


import org.apache.http.Header;
import org.apache.http.HttpHost;
import org.apache.http.HttpRequest;
import org.apache.http.HttpResponse;
import org.apache.http.HttpVersion;
import org.apache.http.conn.ClientConnectionOperator;
import org.apache.http.conn.OperatedClientConnection;
import org.apache.http.conn.scheme.PlainSocketFactory;
import org.apache.http.conn.scheme.Scheme;
import org.apache.http.conn.scheme.SchemeRegistry;
import org.apache.http.conn.scheme.SocketFactory;
import org.apache.http.conn.ssl.SSLSocketFactory;
import org.apache.http.impl.conn.DefaultClientConnectionOperator;
import org.apache.http.message.BasicHttpRequest;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpParams;
import org.apache.http.params.HttpProtocolParams;
import org.apache.http.protocol.HttpContext;
import org.apache.http.protocol.BasicHttpContext;



/**
 * How to open a secure connection through a proxy using
 * {@link ClientConnectionOperator ClientConnectionOperator}.
 * This exemplifies the <i>opening</i> of the connection only.
 * The message exchange, both subsequently and for tunnelling,
 * should not be used as a template.
 *
 * @author <a href="mailto:rolandw at apache.org">Roland Weber</a>
 *
 *
 * <!-- empty lines above to avoid 'svn diff' context problems -->
 * @version $Revision: 645850 $ $Date: 2008-04-08 13:08:52 +0200 (Tue, 08 Apr 2008) $
 *
 * @since 4.0
 */
public class OperatorConnectProxy {

    /**
     * The default parameters.
     * Instantiated in {@link #setup setup}.
     */
    private static HttpParams defaultParameters = null;

    /**
     * The scheme registry.
     * Instantiated in {@link #setup setup}.
     */
    private static SchemeRegistry supportedSchemes;


    /**
     * Main entry point to this example.
     *
     * @param args      ignored
     */
    public final static void main(String[] args)
        throws Exception {

        // make sure to use a proxy that supports CONNECT
        final HttpHost target =
            new HttpHost("issues.apache.org", 443, "https");
        final HttpHost proxy =
            new HttpHost("127.0.0.1", 8666, "http");

        setup(); // some general setup

        // one operator can be used for many connections
        ClientConnectionOperator scop = createOperator();
        OperatedClientConnection conn = scop.createConnection();

        HttpRequest req = createRequest(target);
        HttpContext ctx = createContext();

        System.out.println("opening connection to " + proxy);
        scop.openConnection(conn, proxy, null, ctx, getParams());

        HttpRequest connect = createConnect(target);
        System.out.println("opening tunnel to " + target);
        conn.sendRequestHeader(connect);
        // there is no request entity
        conn.flush();

        System.out.println("receiving confirmation for tunnel");
        HttpResponse connected = conn.receiveResponseHeader();
        System.out.println("----------------------------------------");
        printResponseHeader(connected);
        System.out.println("----------------------------------------");
        int status = connected.getStatusLine().getStatusCode();
        if ((status < 200) || (status > 299)) {
            System.out.println("unexpected status code " + status);
            System.exit(1);
        }
        System.out.println("receiving response body (ignored)");
        conn.receiveResponseEntity(connected);

        // Now we have a tunnel to the target. As we will be creating a
        // layered TLS/SSL socket immediately afterwards, updating the
        // connection with the new target is optional - but good style.
        // The scheme part of the target is already "https", though the
        // connection is not yet switched to the TLS/SSL protocol.
        conn.update(null, target, false, getParams());

        System.out.println("layering secure connection");
        scop.updateSecureConnection(conn, target, ctx, getParams());

        // finally we have the secure connection and can send the request

        System.out.println("sending request");
        conn.sendRequestHeader(req);
        // there is no request entity
        conn.flush();

        System.out.println("receiving response header");
        HttpResponse rsp = conn.receiveResponseHeader();

        System.out.println("----------------------------------------");
        printResponseHeader(rsp);
        System.out.println("----------------------------------------");

        System.out.println("closing connection");
        conn.close();

    } // main


    private final static ClientConnectionOperator createOperator() {
        return new DefaultClientConnectionOperator(supportedSchemes);
    }


    /**
     * Performs general setup.
     * This should be called only once.
     */
    private final static void setup() {

        // Register the "http" and "https" protocol schemes, they are
        // required by the default operator to look up socket factories.
        supportedSchemes = new SchemeRegistry();
        SocketFactory sf = PlainSocketFactory.getSocketFactory();
        supportedSchemes.register(new Scheme("http", sf, 80));
        sf = SSLSocketFactory.getSocketFactory();
        supportedSchemes.register(new Scheme("https", sf, 80));

        // Prepare parameters.
        // Since this example doesn't use the full core framework,
        // only few parameters are actually required.
        HttpParams params = new BasicHttpParams();
        HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
        HttpProtocolParams.setUseExpectContinue(params, false);
        defaultParameters = params;

    } // setup


    private final static HttpParams getParams() {
        return defaultParameters;
    }


    /**
     * Creates a request to tunnel a connection.
     * In a real application, request interceptors should be used
     * to add the required headers.
     *
     * @param target    the target server for the tunnel
     *
     * @return  a CONNECT request without an entity
     */
    private final static HttpRequest createConnect(HttpHost target) {

        // see RFC 2817, section 5.2
        final String authority = target.getHostName()+":"+target.getPort();

        HttpRequest req = new BasicHttpRequest
            ("CONNECT", authority, HttpVersion.HTTP_1_1);

        req.addHeader("Host", authority);

        return req;
    }


    /**
     * Creates a request to execute in this example.
     * In a real application, request interceptors should be used
     * to add the required headers.
     *
     * @param target    the target server for the request
     *
     * @return  a request without an entity
     */
    private final static HttpRequest createRequest(HttpHost target) {

        HttpRequest req = new BasicHttpRequest
            ("OPTIONS", "*", HttpVersion.HTTP_1_1);

        req.addHeader("Host", target.getHostName());

        return req;
    }


    /**
     * Creates a context for executing a request.
     * Since this example doesn't really use the execution framework,
     * the context can be left empty.
     *
     * @return  a new, empty context
     */
    private final static HttpContext createContext() {
        return new BasicHttpContext(null);
    }


    private final static void printResponseHeader(HttpResponse rsp) {

        System.out.println(rsp.getStatusLine());
        Header[] headers = rsp.getAllHeaders();
        for (int i=0; i<headers.length; i++) {
            System.out.println(headers[i]);
        }
    }

} // class OperatorConnectProxy