httpclient使用详解（爬虫）

一、简介

HttpClient是Apache Jakarta Common下的子项目，用来提供高效的、最新的、功能丰富的支持HTTP协议的客户端编程工具包，并且它支持HTTP协议最新的版本和建议。HttpClient已经应用在很多的项目中，比如Apache Jakarta上很著名的另外两个开源项目Cactus和HTMLUnit都使用了HttpClient。

下载地址: http://hc.apache.org/downloads.cgi

二、特性

1. 基于标准、纯净的java语言。实现了Http1.0和Http1.1

2. 以可扩展的面向对象的结构实现了Http全部的方法（GET, POST, PUT, DELETE, HEAD, OPTIONS, and TRACE）。

3. 支持HTTPS协议。

4. 通过Http代理建立透明的连接。

5. 利用CONNECT方法通过Http代理建立隧道的https连接。

6. Basic, Digest, NTLMv1, NTLMv2, NTLM2 Session, SNPNEGO/Kerberos认证方案。

7. 插件式的自定义认证方案。

8. 便携可靠的套接字工厂使它更容易的使用第三方解决方案。

9. 连接管理器支持多线程应用。支持设置最大连接数，同时支持设置每个主机的最大连接数，发现并关闭过期的连接。

10. 自动处理Set-Cookie中的Cookie。

11. 插件式的自定义Cookie策略。

12. Request的输出流可以避免流中内容直接缓冲到socket服务器。

13. Response的输入流可以有效的从socket服务器直接读取相应内容。

14. 在http1.0和http1.1中利用KeepAlive保持持久连接。

15. 直接获取服务器发送的response code和 headers。

16. 设置连接超时的能力。

17. 实验性的支持http1.1 response caching。

18. 源代码基于Apache License 可免费获取。

三、使用方法

使用HttpClient发送请求、接收响应很简单，一般需要如下几步即可。

1. 创建HttpClient对象。

2. 创建请求方法的实例，并指定请求URL。如果需要发送GET请求，创建HttpGet对象；如果需要发送POST请求，创建HttpPost对象。

3. 如果需要发送请求参数，可调用HttpGet、HttpPost共同的setParams(HetpParams params)方法来添加请求参数；对于HttpPost对象而言，也可调用setEntity(HttpEntity entity)方法来设置请求参数。

4. 调用HttpClient对象的execute(HttpUriRequest request)发送请求，该方法返回一个HttpResponse。

5. 调用HttpResponse的getAllHeaders()、getHeaders(String name)等方法可获取服务器的响应头；调用HttpResponse的getEntity()方法可获取HttpEntity对象，该对象包装了服务器的响应内容。程序可通过该对象获取服务器的响应内容。

6. 释放连接。无论执行方法是否成功，都必须释放连接

四、样例

HttpClientRequestHandler类

package com.xiaojiang.httpclient;import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;import java.io.IOException;import java.net.MalformedURLException;import java.util.ArrayList;import java.util.List;import java.util.Map;import java.util.zip.GZIPInputStream;import org.apache.commons.io.IOUtils;import org.apache.http.Header;import org.apache.http.HttpResponse;import org.apache.http.NameValuePair;import org.apache.http.client.HttpClient;import org.apache.http.client.entity.UrlEncodedFormEntity;import org.apache.http.client.methods.HttpGet;import org.apache.http.client.methods.HttpPost;import org.apache.http.message.BasicNameValuePair;import org.apache.http.util.EntityUtils;import org.jsoup.Jsoup;import org.jsoup.nodes.Document;import com.xiaojiang.exception.DataTaskException;public class HttpClientRequestHandler {private static final int ERROR_CODE = 1;/** * get方式提交数据 */public static Document doGet(String url, String proxyIp, Integer proxyPort) throws DataTaskException{//System.out.println("doGet中使用代理："+proxyIp+":"+proxyPort);HttpClient client = HttpConnectionManager.getHttpClient(proxyIp, proxyPort);HttpGet httpGet = new HttpGet(url);httpGet.setHeader("Accept-Language", "zh-cn,zh;q=0.5");httpGet.setHeader("Accept-Charset", "GB2312,utf-8;q=0.7,*;q=0.7");httpGet.setHeader("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");httpGet.setHeader("Accept-Encoding", "gzip, deflate");httpGet.setHeader("User-Agent", HttpUserAgent.get());try{//执行HttpResponse response = client.execute(httpGet);int statuCode = response.getStatusLine().getStatusCode();if(statuCode == 200){String html = formatResponse(response);if(html != null){return Jsoup.parse(html);}return null;} else {throw new DataTaskException(statuCode, "请求URL【"+url+"】，"+statuCode+"错误", null);}} catch (Exception e){throw new DataTaskException(ERROR_CODE, e.getMessage(), e);} finally {if(httpGet != null){httpGet.abort();}}}/** * post方式提交 * @throws DataTaskException  */public static Document doPost(String url, Map<String,String> paramaters, String proxyIp, Integer proxyPort) throws DataTaskException{HttpClient client = HttpConnectionManager.getHttpClient(proxyIp, proxyPort);HttpPost request = new HttpPost(url);request.setHeader("Accept", "application/json, text/javascript, */*; q=0.01");request.setHeader("Accept-Encoding", "gzip, deflate");request.setHeader("Accept-Language", "zh-cn,zh;q=0.8,en-us;q=0.5,en;q=0.3");request.setHeader("Cache-Control", "no-cache");request.setHeader("Connection", "keep-alive");request.setHeader("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");// 创建名/值组列表List<NameValuePair> parameters = new ArrayList<NameValuePair>();for(String key : paramaters.keySet()){parameters.add(new BasicNameValuePair(key, paramaters.get(key)));}try {// 创建UrlEncodedFormEntity对象UrlEncodedFormEntity formEntiry = new UrlEncodedFormEntity(parameters);request.setEntity(formEntiry);// 执行请求HttpResponse response = client.execute(request);int statuCode = response.getStatusLine().getStatusCode();if (statuCode == 200) {String html = formatResponse(response);if(html != null){return Jsoup.parse(html);}return null;} else if (statuCode == 404) {throw new DataTaskException(ERROR_CODE, "请求URL【"+url+"】，404错误", null);}} catch (Exception e) {throw new DataTaskException(ERROR_CODE, e.getMessage(), e);} finally {if(request != null){request.abort();}}return null;}/** * 格式化请求结果 * @throws DataTaskException  */private static String formatResponse(HttpResponse response) throws DataTaskException {ByteArrayInputStream bis = null;try{Header contentEncoding = response.getFirstHeader("Content-Encoding");if(contentEncoding == null){return EntityUtils.toString(response.getEntity(),"UTF-8");} else {String charset = "utf-8";Header contentType = response.getFirstHeader("Content-Type");if(contentType != null){String contentTypeStr = contentType.getValue();if(contentTypeStr != null && !"".equals(contentTypeStr)){charset = contentTypeStr.substring(contentTypeStr.indexOf("=") + 1,contentTypeStr.length());}}String contentEncodingType = contentEncoding.getValue();if(contentEncodingType.equalsIgnoreCase("gzip")){if(response.toString().contains("soufun"))charset = "gb2312";byte[] bytes = IOUtils.toByteArray(response.getEntity().getContent());bis = new ByteArrayInputStream(bytes);return uncompress(bis ,charset);}}} catch(Exception e) {throw new DataTaskException(ERROR_CODE, "格式化HttpResponse出错", e);} finally {if(bis != null){try {bis.close();} catch (IOException e) {throw new DataTaskException(ERROR_CODE, "格式化HttpResponse出错", e);}}}return null;}/** * GZIP解压 */private static String uncompress(ByteArrayInputStream in, String charset) {ByteArrayOutputStream out = new ByteArrayOutputStream();try {GZIPInputStream gunzip = new GZIPInputStream(in);byte[] buffer = new byte[256];int n;while((n = gunzip.read(buffer)) >=0 ){out.write(buffer, 0, n);}return out.toString(charset);} catch (IOException e) {e.printStackTrace();}return null;}}

HttpConnectionManager类

package com.xiaojiang.httpclient;import org.apache.http.HttpHost;import org.apache.http.client.HttpClient;import org.apache.http.conn.ClientConnectionManager;import org.apache.http.conn.params.ConnManagerParams;import org.apache.http.conn.params.ConnPerRouteBean;import org.apache.http.conn.params.ConnRouteParams;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.ssl.SSLSocketFactory;import org.apache.http.impl.client.DefaultHttpClient;import org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager;import org.apache.http.params.BasicHttpParams;import org.apache.http.params.HttpConnectionParams;import org.apache.http.params.HttpParams;public class HttpConnectionManager {private static HttpParams httpParams;private static ClientConnectionManager connectionManager;//最大连接数public final static int MAX_TOTAL_CONNECTIONS = 800;//获取连接的最大等待时间public final static int WAIT_TIMEOUT = 60000;//每个路由最大连接数public final static int MAX_ROUTE_CONNECTIONS = 400;//连接超时时间public final static int CONNECT_TIMEOUT = 60000;//读取超时时间public final static int READ_TIMEOUT = 60000;static {httpParams = new BasicHttpParams();// 设置最大连接数ConnManagerParams.setMaxTotalConnections(httpParams, MAX_TOTAL_CONNECTIONS);// 设置获取连接的最大等待时间ConnManagerParams.setTimeout(httpParams, WAIT_TIMEOUT);// 设置每个路由最大连接数ConnPerRouteBean connPerRoute = new ConnPerRouteBean(MAX_ROUTE_CONNECTIONS);ConnManagerParams.setMaxConnectionsPerRoute(httpParams,connPerRoute);// 设置连接超时时间HttpConnectionParams.setConnectionTimeout(httpParams, CONNECT_TIMEOUT);// 设置读取超时时间HttpConnectionParams.setSoTimeout(httpParams, READ_TIMEOUT);SchemeRegistry registry = new SchemeRegistry();registry.register(new Scheme("http", PlainSocketFactory.getSocketFactory(), 80));registry.register(new Scheme("https", SSLSocketFactory.getSocketFactory(), 443));connectionManager = new ThreadSafeClientConnManager(httpParams, registry);}public static HttpClient getHttpClient(String proxyIp, Integer proxyPort){DefaultHttpClient client = new DefaultHttpClient(connectionManager, httpParams);if(proxyIp !=null && proxyPort !=null){HttpHost proxy = new HttpHost(proxyIp, proxyPort);client.getParams().setParameter(ConnRouteParams.DEFAULT_PROXY, proxy);}return client;}}

HttpUserAgent类package com.xiaojiang.httpclient;

package com.xiaojiang.httpclient;import java.util.ArrayList;import java.util.List;import java.util.Random;public class HttpUserAgent {private static List<String> agents;static{agents = new ArrayList<String>();//IEagents.add("Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0)");agents.add("Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.2)");agents.add("Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)");agents.add("Mozilla/4.0 (compatible; MSIE 5.0; Windows NT)");//Firefox agents.add("Mozilla/5.0 (Windows; U; Windows NT 5.2) Gecko/2008070208 Firefox/3.0.1 ");agents.add("Mozilla/5.0 (Windows; U; Windows NT 5.1) Gecko/20070309 Firefox/2.0.0.3 ");agents.add("Mozilla/5.0 (Windows; U; Windows NT 5.1) Gecko/20070803 Firefox/1.5.0.12");agents.add("Mozilla/5.0 (Windows NT 6.3; WOW64; rv:34.0) Gecko/20100101 Firefox/34.0)");agents.add("Mozilla/5.0 (Windows NT 5.1; rv:5.0) Gecko/20100101 Firefox/5.0");//Opera agents.add("Opera/9.27 (Windows NT 5.2; U; zh-cn)");agents.add("Opera/8.0 (Macintosh; PPC Mac OS X; U; en)");agents.add("Mozilla/5.0 (Macintosh; PPC Mac OS X; U; en) Opera 8.0");//Safari  agents.add("Mozilla/5.0 (Windows; U; Windows NT 5.2) AppleWebKit/525.13 (KHTML, like Gecko) Version/3.1 Safari/525.13");agents.add("Mozilla/5.0 (iPhone; U; CPU like Mac OS X) AppleWebKit/420.1 (KHTML, like Gecko) Version/3.0 Mobile/4A93 Safari/419.3");//Chrome  agents.add("Mozilla/5.0 (Windows; U; Windows NT 5.2) AppleWebKit/525.13 (KHTML, like Gecko) Chrome/0.2.149.27 Safari/525.13");agents.add("Mozilla/5.0 (Windows NT 5.2) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.122 Safari/534.30");//Navigator   agents.add("Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.12) Gecko/20080219 Firefox/2.0.0.12 Navigator/9.0.0.6");//360极速浏览器   agents.add("Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1) ;  QIHU 360EE)");}public static String get(){return agents.get(new Random().nextInt(agents.size()-1));}}