以下实例基于HttpClient 4.3： 

package com.alimama.utils;import java.net.InetAddress;import java.net.UnknownHostException;import java.nio.charset.CodingErrorAction;import java.util.Arrays;import javax.net.ssl.SSLContext;import org.apache.http.Consts;import org.apache.http.Header;import org.apache.http.HttpHost;import org.apache.http.HttpRequest;import org.apache.http.HttpResponse;import org.apache.http.ParseException;import org.apache.http.client.CookieStore;import org.apache.http.client.CredentialsProvider;import org.apache.http.client.config.AuthSchemes;import org.apache.http.client.config.CookieSpecs;import org.apache.http.client.config.RequestConfig;import org.apache.http.client.methods.CloseableHttpResponse;import org.apache.http.client.methods.HttpGet;import org.apache.http.client.protocol.HttpClientContext;import org.apache.http.config.ConnectionConfig;import org.apache.http.config.MessageConstraints;import org.apache.http.config.Registry;import org.apache.http.config.RegistryBuilder;import org.apache.http.config.SocketConfig;import org.apache.http.conn.DnsResolver;import org.apache.http.conn.HttpConnectionFactory;import org.apache.http.conn.ManagedHttpClientConnection;import org.apache.http.conn.routing.HttpRoute;import org.apache.http.conn.socket.ConnectionSocketFactory;import org.apache.http.conn.socket.PlainConnectionSocketFactory;import org.apache.http.conn.ssl.SSLConnectionSocketFactory;import org.apache.http.impl.DefaultHttpResponseFactory;import org.apache.http.impl.client.BasicCookieStore;import org.apache.http.impl.client.BasicCredentialsProvider;import org.apache.http.impl.client.CloseableHttpClient;import org.apache.http.impl.client.DefaultHttpRequestRetryHandler;import org.apache.http.impl.client.HttpClients;import org.apache.http.impl.conn.DefaultHttpResponseParser;import org.apache.http.impl.conn.DefaultHttpResponseParserFactory;import org.apache.http.impl.conn.ManagedHttpClientConnectionFactory;import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;import org.apache.http.impl.conn.SystemDefaultDnsResolver;import org.apache.http.impl.io.DefaultHttpRequestWriterFactory;import org.apache.http.io.HttpMessageParser;import org.apache.http.io.HttpMessageParserFactory;import org.apache.http.io.HttpMessageWriterFactory;import org.apache.http.io.SessionInputBuffer;import org.apache.http.message.BasicHeader;import org.apache.http.message.BasicLineParser;import org.apache.http.message.LineParser;import org.apache.http.ssl.SSLContexts;import org.apache.http.util.CharArrayBuffer;import org.apache.http.util.EntityUtils;/** * This example demonstrates how to customize and configure the most common aspects * of HTTP request execution and connection management. */public class ClientConfiguration {    public final static void main(String[] args) throws Exception {        // Use custom message parser / writer to customize the way HTTP        // messages are parsed from and written out to the data stream.        HttpMessageParserFactory
    
      responseParserFactory = new DefaultHttpResponseParserFactory() {            @Override            public HttpMessageParser
     
       create(                SessionInputBuffer buffer, MessageConstraints constraints) {                LineParser lineParser = new BasicLineParser() {                    @Override                    public Header parseHeader(final CharArrayBuffer buffer) {                        try {                            return super.parseHeader(buffer);                        } catch (ParseException ex) {                            return new BasicHeader(buffer.toString(), null);                        }                    }                };                return new DefaultHttpResponseParser(                    buffer, lineParser, DefaultHttpResponseFactory.INSTANCE, constraints) {                    @Override                    protected boolean reject(final CharArrayBuffer line, int count) {                        // try to ignore all garbage preceding a status line infinitely                        return false;                    }                };            }        };        HttpMessageWriterFactory
      
        requestWriterFactory = new DefaultHttpRequestWriterFactory();        // Use a custom connection factory to customize the process of        // initialization of outgoing HTTP connections. Beside standard connection        // configuration parameters HTTP connection factory can define message        // parser / writer routines to be employed by individual connections.        HttpConnectionFactory
       
         connFactory = new ManagedHttpClientConnectionFactory(                requestWriterFactory, responseParserFactory);        // Client HTTP connection objects when fully initialized can be bound to        // an arbitrary network socket. The process of network socket initialization,        // its connection to a remote address and binding to a local one is controlled        // by a connection socket factory.        // SSL context for secure connections can be created either based on        // system or application specific properties.        SSLContext sslcontext = SSLContexts.createSystemDefault();        // Create a registry of custom connection socket factories for supported        // protocol schemes.        Registry
        
          socketFactoryRegistry = RegistryBuilder.
         
          create() .register("http", PlainConnectionSocketFactory.INSTANCE) .register("https", new SSLConnectionSocketFactory(sslcontext)) .build(); // Use custom DNS resolver to override the system DNS resolution. DnsResolver dnsResolver = new SystemDefaultDnsResolver() { @Override public InetAddress[] resolve(final String host) throws UnknownHostException { if (host.equalsIgnoreCase("myhost")) { return new InetAddress[] { InetAddress.getByAddress(new byte[] {127, 0, 0, 1}) }; } else { return super.resolve(host); } } }; // Create a connection manager with custom configuration. PoolingHttpClientConnectionManager connManager = new PoolingHttpClientConnectionManager( socketFactoryRegistry, connFactory, dnsResolver); // Create socket configuration SocketConfig socketConfig = SocketConfig.custom() .setTcpNoDelay(true) .build(); // Configure the connection manager to use socket configuration either // by default or for a specific host. connManager.setDefaultSocketConfig(socketConfig); connManager.setSocketConfig(new HttpHost("somehost", 80), socketConfig); // Validate connections after 1 sec of inactivity connManager.setValidateAfterInactivity(1000); // Create message constraints MessageConstraints messageConstraints = MessageConstraints.custom() .setMaxHeaderCount(200) .setMaxLineLength(2000) .build(); // Create connection configuration ConnectionConfig connectionConfig = ConnectionConfig.custom() .setMalformedInputAction(CodingErrorAction.IGNORE) .setUnmappableInputAction(CodingErrorAction.IGNORE) .setCharset(Consts.UTF_8) .setMessageConstraints(messageConstraints) .build(); // Configure the connection manager to use connection configuration either // by default or for a specific host. connManager.setDefaultConnectionConfig(connectionConfig); connManager.setConnectionConfig(new HttpHost("somehost", 80), ConnectionConfig.DEFAULT); // Configure total max or per route limits for persistent connections // that can be kept in the pool or leased by the connection manager. connManager.setMaxTotal(100); connManager.setDefaultMaxPerRoute(10); connManager.setMaxPerRoute(new HttpRoute(new HttpHost("somehost", 80)), 20); // Use custom cookie store if necessary. CookieStore cookieStore = new BasicCookieStore(); // Use custom credentials provider if necessary. CredentialsProvider credentialsProvider = new BasicCredentialsProvider(); // Create global request configuration RequestConfig defaultRequestConfig = RequestConfig.custom() .setCookieSpec(CookieSpecs.DEFAULT) .setExpectContinueEnabled(true) .setTargetPreferredAuthSchemes(Arrays.asList(AuthSchemes.NTLM, AuthSchemes.DIGEST)) .setProxyPreferredAuthSchemes(Arrays.asList(AuthSchemes.BASIC)) .build(); // Create an HttpClient with the given custom dependencies and configuration. CloseableHttpClient httpclient = HttpClients.custom() .setConnectionManager(connManager) .setDefaultCookieStore(cookieStore) .setDefaultCredentialsProvider(credentialsProvider) .setProxy(new HttpHost("myproxy", 8080)) .setDefaultRequestConfig(defaultRequestConfig) .setRetryHandler(new DefaultHttpRequestRetryHandler(0,false)) .build(); try { HttpGet httpget = new HttpGet("http://httpbin.org/get"); // Request configuration can be overridden at the request level. // They will take precedence over the one set at the client level. RequestConfig requestConfig = RequestConfig.copy(defaultRequestConfig) .setSocketTimeout(5000) .setConnectTimeout(5000) .setConnectionRequestTimeout(5000) .setProxy(new HttpHost("myotherproxy", 8080)) .build(); httpget.setConfig(requestConfig); // Execution context can be customized locally. HttpClientContext context = HttpClientContext.create(); // Contextual attributes set the local context level will take // precedence over those set at the client level. context.setCookieStore(cookieStore); context.setCredentialsProvider(credentialsProvider); System.out.println("executing request " + httpget.getURI()); CloseableHttpResponse response = httpclient.execute(httpget, context); try { System.out.println("----------------------------------------"); System.out.println(response.getStatusLine()); System.out.println(EntityUtils.toString(response.getEntity())); System.out.println("----------------------------------------"); // Once the request has been executed the local context can // be used to examine updated state and various objects affected // by the request execution. // Last executed request context.getRequest(); // Execution route context.getHttpRoute(); // Target auth state context.getTargetAuthState(); // Proxy auth state context.getTargetAuthState(); // Cookie origin context.getCookieOrigin(); // Cookie spec used context.getCookieSpec(); // User security token context.getUserToken(); } finally { response.close(); } } finally { httpclient.close(); } }}