Android Studio——HttpClient

原文链接：http://huangrongyou.iteye.com/blog/1748722

简要介绍

HttpComponents 包括 HttpCore包和HttpClient包

HttpClient：Http的执行http请求

DefaultHttpClient：httpClient默认实现

HttpGet、HttpPost：Get、Post方法执行类

HttpResponse：执行返回的Response，含http的header和执行结果实体Entity

HttpEntity：Http返回结果实体，不含Header内容

HttpParam：连接参数，配合连接池使用

PoolingClientConnectionManager：连接池

 

基础Get方法

 // 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( entity.getContentEncoding());
     System.out.println( entity.getContentType());
     // 得到返回的主体内容.
     InputStream instream = entity.getContent();
     BufferedReader reader = new BufferedReader(new InputStreamReader(instream, encoding));
     System.out.println(reader.readLine());
     // EntityUtils 处理HttpEntity的工具类
     // System.out.println(EntityUtils.toString(entity));
 }

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

 

 

基础Post方法

 

     DefaultHttpClient httpclient = new DefaultHttpClient();
     HttpPost httpost = new HttpPost(url);
     // 添加参数
     List<NameValuePair> formparams = new ArrayList<NameValuePair>();
     formparams.add(new BasicNameValuePair("p", "1"));
     formparams.add(new BasicNameValuePair("t", "2"));
     formparams.add(new BasicNameValuePair("e", "3"));

     UrlEncodedFormEntity urlEntity =  new UrlEncodedFormEntity(formparams, "UTF-8");
     httpost.setEntity(urlEntity);

     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();
     for (int i = 0; i < cookies.size(); i++) {
         System.out.println("- " + cookies.get(i).toString());
     }
     // 关闭请求
     httpclient.getConnectionManager().shutdown();

 

 

保留Session，保留用户+密码状态

Demo1，只支持单线程

 

 DefaultHttpClient httpclient = new DefaultHttpClient(
     new ThreadSafeClientConnManager());

 HttpPost httpost = new HttpPost(url);
 // 添加参数
 List<NameValuePair> formparams = new ArrayList<NameValuePair>();
 formparams.add(new BasicNameValuePair("p", "1"));
 formparams.add(new BasicNameValuePair("t", "2"));
 formparams.add(new BasicNameValuePair("e", "3"));
 // 设置请求的编码格式
 httpost.setEntity(new UrlEncodedFormEntity(formparams, 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));
 httpclient.getConnectionManager().shutdown();

 return "";

 

 

 

Demo2：第二次请求带上第一次请求的Cookie 

    用于在用户+密码等候后，后续根据第一次请求的URL获取的Cookie，把这些Cookie添加到第二次请求的Cookie中

 

 

 DefaultHttpClient httpclient = new DefaultHttpClient();
         HttpPost httpost = new HttpPost(url);
         // 添加参数
         List<NameValuePair> formparams = new ArrayList<NameValuePair>();
         formparams.add(new BasicNameValuePair("uname", name));
         formparams.add(new BasicNameValuePair("pass", "e0c10f451217b93f76c2654b2b729b85"));
         formparams.add(new BasicNameValuePair("auto_login","0"));
         formparams.add(new BasicNameValuePair("a","1"));
         formparams.add(new BasicNameValuePair("backurl","1"));

         UrlEncodedFormEntity urlEntity =  new UrlEncodedFormEntity(formparams, "UTF-8");
         httpost.setEntity(urlEntity);
         HttpContext localContext = new BasicHttpContext();

         HttpResponse response = httpclient.execute(httpost,localContext);
         HttpEntity entity = response.getEntity();
         // 打印获取值
         System.out.println(Arrays.toString(response.getAllHeaders()));
         System.out.println(EntityUtils.toString(entity));

         // 第二次请求，使用上一次请求的Cookie
         DefaultHttpClient httpclient2 = new DefaultHttpClient();
         HttpPost httpost2 = new HttpPost("http://my.ifeng.com/?_c=index&_a=my");
         // 获取上一次请求的Cookie
         CookieStore cookieStore2 = httpclient2.getCookieStore();
         // 下一次的Cookie的值，将使用上一次请求
         CookieStore cookieStore = httpclient.getCookieStore();
         List<Cookie> list = cookieStore.getCookies();
         for(Cookie o : list){
             System.out.println(o.getName() + " = " + o.getValue() + " 12");;
             cookieStore2.addCookie(o);
         }

         HttpResponse response2 = httpclient2.execute(httpost2);
         HttpEntity entity2 = response2.getEntity();
         System.out.println(Arrays.toString(response2.getAllHeaders()));
         System.out.println(EntityUtils.toString(entity2));

 

 

 

获取访问上下文：

 

 

 HttpClient httpclient = new DefaultHttpClient();
 // 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());
 }

 

 

 

 

连接池和代理：

   每次使用最后一句new DefaultHttpClient(cm, httpParams);获取新的HttpClient

   里面还有一条如何设置代理

 

         // HttpParams
         HttpParams httpParams  = new BasicHttpParams();
         // HttpConnectionParams 设置连接参数
          // 设置连接超时时间
         HttpConnectionParams.setConnectionTimeout(httpParams, 30000);
         // 设置读取超时时间
         HttpConnectionParams.setSoTimeout(httpParams, 60000);

         SchemeRegistry schemeRegistry = new SchemeRegistry();
         schemeRegistry.register(
                  new Scheme("http", 80, PlainSocketFactory.getSocketFactory()));
 //      schemeRegistry.register(
 //               new Scheme("https", 443, SSLSocketFactory.getSocketFactory()));
         PoolingClientConnectionManager cm = new PoolingClientConnectionManager(schemeRegistry);
         // 设置最大连接数
         cm.setMaxTotal(200);
         // 设置每个路由默认最大连接数
         cm.setDefaultMaxPerRoute(20);
 //      // 设置代理和代理最大路由
 //      HttpHost localhost = new HttpHost("locahost", 80);
 //      cm.setMaxPerRoute(new HttpRoute(localhost), 50);
         // 设置代理，
         HttpHost proxy = new HttpHost("10.36.24.3", 60001);
         httpParams.setParameter(ConnRoutePNames.DEFAULT_PROXY,  proxy);

         HttpClient httpClient = new DefaultHttpClient(cm, httpParams);

 

自动重连

   如果某次请求请求失败，可以自动重连

 

 DefaultHttpClient httpClient = new DefaultHttpClient();
             // 可以自动重连
             HttpRequestRetryHandler requestRetryHandler2 = new HttpRequestRetryHandler() {
                 // 自定义的恢复策略
                 public synchronized boolean retryRequest(IOException exception, int executionCount, HttpContext context) {
                     // 设置恢复策略，在发生异常时候将自动重试3次
                     if (executionCount > 3) {
                         // 超过最大次数则不需要重试
                         return false;
                     }
                     if (exception instanceof NoHttpResponseException) {
                         // 服务停掉则重新尝试连接
                         return true;
                     }
                     if (exception instanceof SSLHandshakeException) {
                         // SSL异常不需要重试
                         return false;
                     }
                     HttpRequest request = (HttpRequest) context.getAttribute(ExecutionContext.HTTP_REQUEST);
                     boolean idempotent = (request instanceof HttpEntityEnclosingRequest);
                     if (!idempotent) {
                         // 请求内容相同则重试
                         return true;
                     }
                     return false;
                 }
             };
             httpClient.setHttpRequestRetryHandler(requestRetryHandler2);

 

 

 

 

 

使用自定义ResponseHandler处理返回的请求

 

 

 HttpClient httpClient = new DefaultHttpClient();
 HttpGet get = new HttpGet(url);
     // 定义一个类处理URL返回的结果
     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;
             }
         }
     };
     // 不同于 httpClient.execute(request)，返回值是HttpResponse；返回值右ResponseHandler决定
     byte[] charts = httpClient.execute(get, handler);
     FileOutputStream out = new FileOutputStream(fileName);
     out.write(charts);
     out.close();

     httpClient.getConnectionManager().shutdown();