HttpClient4.2.2的几个常用方法,登录之后访问页面问题,下载文件

在工作中要用到android，然后进行网络请求的时候，打算使用httpClient。

总结一下httpClient的一些基本使用。

版本是4.2.2。

使用这个版本的过程中，百度很多，结果都是出现的org.apache.commons.httpclient.这个包名，而不是我这里的org.apache.http.client.HttpClient----------前者版本是Commons HttpClient 3.x ，不是最新的版本HttpClient 4.×。

官网上面：

1.基本的get

Java代码

1. public void getUrl(String url, String encoding) 
2.             throws ClientProtocolException, IOException { 
3.         // 默认的client类。 
4.         HttpClient client = new DefaultHttpClient(); 
5.         // 设置为get取连接的方式. 
6.         HttpGet get = new HttpGet(url); 
7.         // 得到返回的response. 
8.         HttpResponse response = client.execute(get); 
9.         // 得到返回的client里面的实体对象信息. 
10.         HttpEntity entity = response.getEntity(); 
11.         if (entity != null) { 
12.             System.out.println("内容编码是：" + entity.getContentEncoding()); 
13.             System.out.println("内容类型是：" + entity.getContentType()); 
14.             // 得到返回的主体内容. 
15.             InputStream instream = entity.getContent(); 
16.             try { 
17.                 BufferedReader reader = new BufferedReader( 
18.                         new InputStreamReader(instream, encoding)); 
19.                 System.out.println(reader.readLine()); 
20.             } catch (Exception e) { 
21.                 e.printStackTrace(); 
22.             } finally { 
23.                 instream.close(); 
24.             } 
25.         } 
26.  
27.         // 关闭连接. 
28.         client.getConnectionManager().shutdown(); 
29.     } 

public void getUrl(String url, String encoding)
			throws ClientProtocolException, IOException {
		// 默认的client类。
		HttpClient client = new DefaultHttpClient();
		// 设置为get取连接的方式.
		HttpGet get = new HttpGet(url);
		// 得到返回的response.
		HttpResponse response = client.execute(get);
		// 得到返回的client里面的实体对象信息.
		HttpEntity entity = response.getEntity();
		if (entity != null) {
			System.out.println("内容编码是：" + entity.getContentEncoding());
			System.out.println("内容类型是：" + entity.getContentType());
			// 得到返回的主体内容.
			InputStream instream = entity.getContent();
			try {
				BufferedReader reader = new BufferedReader(
						new InputStreamReader(instream, encoding));
				System.out.println(reader.readLine());
			} catch (Exception e) {
				e.printStackTrace();
			} finally {
				instream.close();
			}
		}

		// 关闭连接.
		client.getConnectionManager().shutdown();
	}

2.基本的Post

   下面的params参数，是在表单里面提交的参数。

Java代码

1. public void postUrlWithParams(String url, Map params, String encoding) 
2.             throws Exception { 
3.         DefaultHttpClient httpclient = new DefaultHttpClient(); 
4.         try { 
5.  
6.             HttpPost httpost = new HttpPost(url); 
7.             // 添加参数 
8.             List<NameValuePair> nvps = new ArrayList<NameValuePair>(); 
9.             if (params != null && params.keySet().size() >0) { 
10.                 Iterator iterator = params.entrySet().iterator(); 
11.                 while (iterator.hasNext()) { 
12.                     Map.Entry entry = (Entry) iterator.next(); 
13.                     nvps.add(new BasicNameValuePair((String) entry.getKey(), 
14.                             (String) entry.getValue())); 
15.                 } 
16.             } 
17.  
18.             httpost.setEntity(new UrlEncodedFormEntity(nvps, Consts.UTF_8)); 
19.  
20.             HttpResponse response = httpclient.execute(httpost); 
21.             HttpEntity entity = response.getEntity(); 
22.  
23.             System.out.println("Login form get: " + response.getStatusLine() 
24.                     + entity.getContent()); 
25.             dump(entity, encoding); 
26.             System.out.println("Post logon cookies:"); 
27.             List<Cookie> cookies = httpclient.getCookieStore().getCookies(); 
28.             if (cookies.isEmpty()) { 
29.                 System.out.println("None"); 
30.             } else { 
31.                 for (int i =0; i < cookies.size(); i++) { 
32.                     System.out.println("- " + cookies.get(i).toString()); 
33.                 } 
34.             } 
35.  
36.         } finally { 
37.             // 关闭请求 
38.             httpclient.getConnectionManager().shutdown(); 
39.         } 
40.     } 

public void postUrlWithParams(String url, Map params, String encoding)
			throws Exception {
		DefaultHttpClient httpclient = new DefaultHttpClient();
		try {

			HttpPost httpost = new HttpPost(url);
			// 添加参数
			List<NameValuePair> nvps = new ArrayList<NameValuePair>();
			if (params != null && params.keySet().size() > 0) {
				Iterator iterator = params.entrySet().iterator();
				while (iterator.hasNext()) {
					Map.Entry entry = (Entry) iterator.next();
					nvps.add(new BasicNameValuePair((String) entry.getKey(),
							(String) entry.getValue()));
				}
			}

			httpost.setEntity(new UrlEncodedFormEntity(nvps, Consts.UTF_8));

			HttpResponse response = httpclient.execute(httpost);
			HttpEntity entity = response.getEntity();

			System.out.println("Login form get: " + response.getStatusLine()
					+ entity.getContent());
			dump(entity, encoding);
			System.out.println("Post logon cookies:");
			List<Cookie> cookies = httpclient.getCookieStore().getCookies();
			if (cookies.isEmpty()) {
				System.out.println("None");
			} else {
				for (int i = 0; i < cookies.size(); i++) {
					System.out.println("- " + cookies.get(i).toString());
				}
			}

		} finally {
			// 关闭请求
			httpclient.getConnectionManager().shutdown();
		}
	}

3。打印页面输出的小代码片段

Java代码

1. private staticvoid dump(HttpEntity entity, String encoding) 
2.             throws IOException { 
3.         BufferedReader br = new BufferedReader(new InputStreamReader( 
4.                 entity.getContent(), encoding)); 
5.         System.out.println(br.readLine()); 
6.     } 

private static void dump(HttpEntity entity, String encoding)
			throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(
				entity.getContent(), encoding));
		System.out.println(br.readLine());
	}

4.常见的登录session问题，需求:使用账户，密码登录系统之后，然后再访问页面不出错。

特别注意，下面的httpclient对象要使用一个，而不要在第二次访问的时候，重新new一个。至于如何保存这个第一步经过了验证的httpclient，有很多种方法实现。单例，系统全局变量（android 下面的Application），ThreadLocal变量等等。

       以及下面创建的httpClient要使用ThreadSafeClientConnManager对象！

   public String getSessionId(String url, Map params, String encoding,

Java代码

1.         String url2) throws Exception { 
2.     DefaultHttpClient httpclient = new DefaultHttpClient( 
3.             new ThreadSafeClientConnManager()); 
4.     try { 
5.  
6.         HttpPost httpost = new HttpPost(url); 
7.         // 添加参数 
8.         List<NameValuePair> nvps = new ArrayList<NameValuePair>(); 
9.         if (params != null && params.keySet().size() >0) { 
10.             Iterator iterator = params.entrySet().iterator(); 
11.             while (iterator.hasNext()) { 
12.                 Map.Entry entry = (Entry) iterator.next(); 
13.                 nvps.add(new BasicNameValuePair((String) entry.getKey(), 
14.                         (String) entry.getValue())); 
15.             } 
16.         } 
17.         // 设置请求的编码格式 
18.         httpost.setEntity(new UrlEncodedFormEntity(nvps, Consts.UTF_8)); 
19.         // 登录一遍 
20.         httpclient.execute(httpost); 
21.         // 然后再第二次请求普通的url即可。 
22.         httpost = new HttpPost(url2); 
23.         BasicResponseHandler responseHandler = new BasicResponseHandler(); 
24.         System.out.println(httpclient.execute(httpost, responseHandler)); 
25.     } finally { 
26.         // 关闭请求 
27.         httpclient.getConnectionManager().shutdown(); 
28.     } 
29.     return ""; 
30. } 

			String url2) throws Exception {
		DefaultHttpClient httpclient = new DefaultHttpClient(
				new ThreadSafeClientConnManager());
		try {

			HttpPost httpost = new HttpPost(url);
			// 添加参数
			List<NameValuePair> nvps = new ArrayList<NameValuePair>();
			if (params != null && params.keySet().size() > 0) {
				Iterator iterator = params.entrySet().iterator();
				while (iterator.hasNext()) {
					Map.Entry entry = (Entry) iterator.next();
					nvps.add(new BasicNameValuePair((String) entry.getKey(),
							(String) entry.getValue()));
				}
			}
			// 设置请求的编码格式
			httpost.setEntity(new UrlEncodedFormEntity(nvps, Consts.UTF_8));
			// 登录一遍
			httpclient.execute(httpost);
			// 然后再第二次请求普通的url即可。
			httpost = new HttpPost(url2);
			BasicResponseHandler responseHandler = new BasicResponseHandler();
			System.out.println(httpclient.execute(httpost, responseHandler));
		} finally {
			// 关闭请求
			httpclient.getConnectionManager().shutdown();
		}
		return "";
	}

5.下载文件，例如mp3等等。

Java代码

1. //第一个参数，网络连接；第二个参数，保存到本地文件的地址 
2. public void getFile(String url, String fileName) { 
3.         HttpClient httpClient = new DefaultHttpClient(); 
4.         HttpGet get = new HttpGet(url); 
5.         try { 
6.             ResponseHandler<byte[]> handler =new ResponseHandler<byte[]>() { 
7.                 public byte[] handleResponse(HttpResponse response) 
8.                         throws ClientProtocolException, IOException { 
9.                     HttpEntity entity = response.getEntity(); 
10.                     if (entity != null) { 
11.                         return EntityUtils.toByteArray(entity); 
12.                     } else { 
13.                         return null; 
14.                     } 
15.                 } 
16.             }; 
17.  
18.             byte[] charts = httpClient.execute(get, handler); 
19.             FileOutputStream out = new FileOutputStream(fileName); 
20.             out.write(charts); 
21.             out.close(); 
22.  
23.         } catch (Exception e) { 
24.             e.printStackTrace(); 
25.         } finally { 
26.             httpClient.getConnectionManager().shutdown(); 
27.         } 
28.     } 

//第一个参数，网络连接；第二个参数，保存到本地文件的地址
public void getFile(String url, String fileName) {
		HttpClient httpClient = new DefaultHttpClient();
		HttpGet get = new HttpGet(url);
		try {
			ResponseHandler<byte[]> handler = new ResponseHandler<byte[]>() {
				public byte[] handleResponse(HttpResponse response)
						throws ClientProtocolException, IOException {
					HttpEntity entity = response.getEntity();
					if (entity != null) {
						return EntityUtils.toByteArray(entity);
					} else {
						return null;
					}
				}
			};

			byte[] charts = httpClient.execute(get, handler);
			FileOutputStream out = new FileOutputStream(fileName);
			out.write(charts);
			out.close();

		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			httpClient.getConnectionManager().shutdown();
		}
	}

6.创建一个多线程环境下面可用的httpClient

（原文：http://blog.csdn.net/jiaoshi0531/article/details/6459468）

Java代码

1.               HttpParams params = new BasicHttpParams(); 
2. //设置允许链接的做多链接数目 
3. ConnManagerParams.setMaxTotalConnections(params, 200); 
4. //设置超时时间. 
5. ConnManagerParams.setTimeout(params, 10000); 
6. //设置每个路由的最多链接数量是20 
7. ConnPerRouteBean connPerRoute = new ConnPerRouteBean(20); 
8. //设置到指定主机的路由的最多数量是50 
9. HttpHost localhost = new HttpHost("127.0.0.1",80); 
10. connPerRoute.setMaxForRoute(new HttpRoute(localhost),50); 
11. ConnManagerParams.setMaxConnectionsPerRoute(params, connPerRoute); 
12. //设置链接使用的版本 
13. HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1); 
14. //设置链接使用的内容的编码 
15. HttpProtocolParams.setContentCharset(params, 
16.         HTTP.DEFAULT_CONTENT_CHARSET); 
17. //是否希望可以继续使用. 
18. HttpProtocolParams.setUseExpectContinue(params, true); 
19.  
20. SchemeRegistry schemeRegistry = new SchemeRegistry(); 
21. schemeRegistry.register(new Scheme("http",PlainSocketFactory.getSocketFactory(),80)); 
22. schemeRegistry.register(new Scheme("https",SSLSocketFactory.getSocketFactory(),443)); 
23. ClientConnectionManager cm = new ThreadSafeClientConnManager(params,schemeRegistry); 
24. httpClient = new DefaultHttpClient(cm, params);  

                HttpParams params = new BasicHttpParams();
		//设置允许链接的做多链接数目
		ConnManagerParams.setMaxTotalConnections(params, 200);
		//设置超时时间.
		ConnManagerParams.setTimeout(params, 10000);
		//设置每个路由的最多链接数量是20
		ConnPerRouteBean connPerRoute = new ConnPerRouteBean(20);
		//设置到指定主机的路由的最多数量是50
		HttpHost localhost = new HttpHost("127.0.0.1",80);
		connPerRoute.setMaxForRoute(new HttpRoute(localhost), 50);
		ConnManagerParams.setMaxConnectionsPerRoute(params, connPerRoute);
		//设置链接使用的版本
		HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
		//设置链接使用的内容的编码
		HttpProtocolParams.setContentCharset(params,
				HTTP.DEFAULT_CONTENT_CHARSET);
		//是否希望可以继续使用.
		HttpProtocolParams.setUseExpectContinue(params, true);
		
		SchemeRegistry schemeRegistry = new SchemeRegistry();
		schemeRegistry.register(new Scheme("http",PlainSocketFactory.getSocketFactory(),80));
		schemeRegistry.register(new Scheme("https",SSLSocketFactory.getSocketFactory(),443));
		ClientConnectionManager cm = new ThreadSafeClientConnManager(params,schemeRegistry);
		httpClient = new DefaultHttpClient(cm, params); 

7.实用的一个对象，http上下文，可以从这个对象里面取到一次请求相关的信息，例如request，response，代理主机等。

Java代码

1. public staticvoid getUrl(String url, String encoding) 
2.             throws ClientProtocolException, IOException { 
3.         // 设置为get取连接的方式. 
4.         HttpGet get = new HttpGet(url); 
5.         HttpContext localContext = new BasicHttpContext(); 
6.         // 得到返回的response.第二个参数，是上下文，很好的一个参数！ 
7.         httpclient.execute(get, localContext); 
8.  
9.         // 从上下文中得到HttpConnection对象 
10.         HttpConnection con = (HttpConnection) localContext 
11.                 .getAttribute(ExecutionContext.HTTP_CONNECTION); 
12.         System.out.println("socket超时时间：" + con.getSocketTimeout()); 
13.  
14.         // 从上下文中得到HttpHost对象 
15.         HttpHost target = (HttpHost) localContext 
16.                 .getAttribute(ExecutionContext.HTTP_TARGET_HOST); 
17.         System.out.println("最终请求的目标:" + target.getHostName() +":" 
18.                 + target.getPort()); 
19.  
20.         // 从上下文中得到代理相关信息. 
21.         HttpHost proxy = (HttpHost) localContext 
22.                 .getAttribute(ExecutionContext.HTTP_PROXY_HOST); 
23.         if (proxy != null) 
24.             System.out.println("代理主机的目标:" + proxy.getHostName() +":" 
25.                     + proxy.getPort()); 
26.  
27.         System.out.println("是否发送完毕:" 
28.                 + localContext.getAttribute(ExecutionContext.HTTP_REQ_SENT)); 
29.  
30.         // 从上下文中得到HttpRequest对象 
31.         HttpRequest request = (HttpRequest) localContext 
32.                 .getAttribute(ExecutionContext.HTTP_REQUEST); 
33.         System.out.println("请求的版本:" + request.getProtocolVersion()); 
34.         Header[] headers = request.getAllHeaders(); 
35.         System.out.println("请求的头信息: "); 
36.         for (Header h : headers) { 
37.             System.out.println(h.getName() + "--" + h.getValue()); 
38.         } 
39.         System.out.println("请求的链接:" + request.getRequestLine().getUri()); 
40.  
41.         // 从上下文中得到HttpResponse对象 
42.         HttpResponse response = (HttpResponse) localContext 
43.                 .getAttribute(ExecutionContext.HTTP_RESPONSE); 
44.         HttpEntity entity = response.getEntity(); 
45.         if (entity != null) { 
46.             System.out.println("返回结果内容编码是：" + entity.getContentEncoding()); 
47.             System.out.println("返回结果内容类型是：" + entity.getContentType()); 
48.             dump(entity, encoding); 
49.         } 
50.     } 

public static void getUrl(String url, String encoding)
			throws ClientProtocolException, IOException {
		// 设置为get取连接的方式.
		HttpGet get = new HttpGet(url);
		HttpContext localContext = new BasicHttpContext();
		// 得到返回的response.第二个参数，是上下文，很好的一个参数！
		httpclient.execute(get, localContext);

		// 从上下文中得到HttpConnection对象
		HttpConnection con = (HttpConnection) localContext
				.getAttribute(ExecutionContext.HTTP_CONNECTION);
		System.out.println("socket超时时间：" + con.getSocketTimeout());

		// 从上下文中得到HttpHost对象
		HttpHost target = (HttpHost) localContext
				.getAttribute(ExecutionContext.HTTP_TARGET_HOST);
		System.out.println("最终请求的目标:" + target.getHostName() + ":"
				+ target.getPort());

		// 从上下文中得到代理相关信息.
		HttpHost proxy = (HttpHost) localContext
				.getAttribute(ExecutionContext.HTTP_PROXY_HOST);
		if (proxy != null)
			System.out.println("代理主机的目标:" + proxy.getHostName() + ":"
					+ proxy.getPort());

		System.out.println("是否发送完毕:"
				+ localContext.getAttribute(ExecutionContext.HTTP_REQ_SENT));

		// 从上下文中得到HttpRequest对象
		HttpRequest request = (HttpRequest) localContext
				.getAttribute(ExecutionContext.HTTP_REQUEST);
		System.out.println("请求的版本:" + request.getProtocolVersion());
		Header[] headers = request.getAllHeaders();
		System.out.println("请求的头信息: ");
		for (Header h : headers) {
			System.out.println(h.getName() + "--" + h.getValue());
		}
		System.out.println("请求的链接:" + request.getRequestLine().getUri());

		// 从上下文中得到HttpResponse对象
		HttpResponse response = (HttpResponse) localContext
				.getAttribute(ExecutionContext.HTTP_RESPONSE);
		HttpEntity entity = response.getEntity();
		if (entity != null) {
			System.out.println("返回结果内容编码是：" + entity.getContentEncoding());
			System.out.println("返回结果内容类型是：" + entity.getContentType());
			dump(entity, encoding);
		}
	}

输出结果大致如下：

Txt代码

1. socket超时时间：0 
2. 最终请求的目标:money.finance.sina.com.cn:-1 
3. 是否发送完毕:true 
4. 请求的版本:HTTP/1.1 
5. 请求的头信息:  
6. Host--money.finance.sina.com.cn 
7. Connection--Keep-Alive 
8. User-Agent--Apache-HttpClient/4.2.2 (java1.5) 
9. 请求的链接:/corp/go.php/vFD_BalanceSheet/stockid/600031/ctrl/part/displaytype/4.phtml 
10. 返回结果内容编码是：null 
11. 返回结果内容类型是：Content-Type: text/html 

socket超时时间：0
最终请求的目标:money.finance.sina.com.cn:-1
是否发送完毕:true
请求的版本:HTTP/1.1
请求的头信息: 
Host--money.finance.sina.com.cn
Connection--Keep-Alive
User-Agent--Apache-HttpClient/4.2.2 (java 1.5)
请求的链接:/corp/go.php/vFD_BalanceSheet/stockid/600031/ctrl/part/displaytype/4.phtml
返回结果内容编码是：null
返回结果内容类型是：Content-Type: text/html

8.设置代理

Java代码

1.              //String  hostIp代理主机ip,int port  代理端口 
2. tpHost proxy = new HttpHost(hostIp, port); 
3. // 设置代理主机. 
4. tpclient.getParams().setParameter(ConnRoutePNames.DEFAULT_PROXY, 
5. proxy); 

               //String  hostIp代理主机ip,int port  代理端口
HttpHost proxy = new HttpHost(hostIp, port);
		// 设置代理主机.
httpclient.getParams().setParameter(ConnRoutePNames.DEFAULT_PROXY,
		proxy);

9.设置保持链接时间

Java代码

1. //在服务端设置一个保持持久连接的特性. 
2.         //HTTP服务器配置了会取消在一定时间内没有活动的链接，以节省系统的持久性链接资源. 
3.         httpClient.setKeepAliveStrategy(new ConnectionKeepAliveStrategy() { 
4.             public long getKeepAliveDuration(HttpResponse response, 
5.                     HttpContext context) { 
6.                 HeaderElementIterator it = new BasicHeaderElementIterator( 
7.                         response.headerIterator(HTTP.CONN_KEEP_ALIVE)); 
8.                 while (it.hasNext()) { 
9.                     HeaderElement he = it.nextElement(); 
10.                     String param = he.getName(); 
11.                     String value = he.getValue(); 
12.                     if (value != null && param.equalsIgnoreCase("timeout")) { 
13.                         try { 
14.                             return Long.parseLong(value) *1000; 
15.                         } catch (Exception e) { 
16.  
17.                         } 
18.                     } 
19.                 } 
20.                 HttpHost target = (HttpHost)context.getAttribute(ExecutionContext.HTTP_TARGET_HOST); 
21.                 if("www.baidu.com".equalsIgnoreCase(target.getHostName())){ 
22.                     return 5*1000; 
23.                 } 
24.                 else 
25.                     return 30*1000;  
26.             }  
27.         }); 

//在服务端设置一个保持持久连接的特性.
		//HTTP服务器配置了会取消在一定时间内没有活动的链接，以节省系统的持久性链接资源.
		httpClient.setKeepAliveStrategy(new ConnectionKeepAliveStrategy() {
			public long getKeepAliveDuration(HttpResponse response,
					HttpContext context) {
				HeaderElementIterator it = new BasicHeaderElementIterator(
						response.headerIterator(HTTP.CONN_KEEP_ALIVE));
				while (it.hasNext()) {
					HeaderElement he = it.nextElement();
					String param = he.getName();
					String value = he.getValue();
					if (value != null && param.equalsIgnoreCase("timeout")) {
						try {
							return Long.parseLong(value) * 1000;
						} catch (Exception e) {

						}
					}
				}
				HttpHost target = (HttpHost)context.getAttribute(ExecutionContext.HTTP_TARGET_HOST);
				if("www.baidu.com".equalsIgnoreCase(target.getHostName())){
					return 5*1000;
				}
				else
					return 30*1000; 
			} 
		});

转账注明出处：http://renjie120.iteye.com/blog/1727933