用Java模拟Http请求

1），利用httpclient4.× 写一个http的客户端，模拟浏览器请求， 

 public void post(List<NameValuePair> payload) throws  Exception{
         HttpPost post = new HttpPost(uri);
         HttpEntity result = null;
         try {
             UrlEncodedFormEntity entity = new UrlEncodedFormEntity(payload,
                     charset);
             post.setEntity(entity);
             if (LOG.isDebugEnabled()) {
                 LOG.debug("sending:" + payload);
             }

             HttpResponse response = _httpClient.execute(post);
             StatusLine statusLine = response.getStatusLine();
             if (statusLine.getStatusCode() != HttpStatus.SC_OK) {
                 result = response.getEntity();
                 StringBuilder msg = new StringBuilder();
                 msg.append("http response with code "
                         + statusLine.getStatusCode());
                 msg.append("\n");
                 msg.append("post request: " + post.getURI());
                 msg.append("\n");
                 msg.append(statusLine.getReasonPhrase());
                 if (result != null) {
                     msg.append("\n\n");
                     msg.append(EntityUtils.toString(result, "UTF-8"));
                     msg.append("\n\n");
                 }
                 throw new UmcException(msg.toString());
             }
             if (response.getEntity() != null) {
                 BufferedReader reader = new BufferedReader(
                         new InputStreamReader(
                                 response.getEntity().getContent(), "UTF-8"));
                 String line = null;
                 while ((line = reader.readLine()) != null) {
                     if (line.indexOf("success") < 0)
                         System.out.println(line);
                 }
             }
         } finally {
             if (result != null)
                 try {
                     EntityUtils.consume(result);
                 } catch (IOException e) {
                 }
             post.abort();
         }
     }

uri是请求的地址，charset是编码“UTF-8”,List<NameValuePair>就是表单参数集 

 ClientConnectionManager     ccManager = new ThreadSafeClientConnManager();
 HttpClient      _httpClient = new DefaultHttpClient(ccManager);

2) 采用JDK的HttpConnection构造http客户端， 

 ////发送
     HttpURLConnection conn = null;
     try {
         URL url = new URL(Your_URL);
         conn = (HttpURLConnection) url.openConnection();
         conn.setRequestMethod("POST");
         conn.setRequestProperty("Content-Type",
                 "application/x-www-form-urlencoded");
         conn.setUseCaches(false);
         conn.setDoOutput(true);
         OutputStreamWriter osw = new OutputStreamWriter(
                 conn.getOutputStream());
         StringBuffer sb = new StringBuffer();
         addPair(sb, "p1", "p1value");
         addPair(sb, "p2", "p2value");
         osw.write(sb.substring(0, sb.length() - 1));
         osw.flush();
         BufferedReader reader = new BufferedReader(
                 new InputStreamReader(conn.getInputStream()));
         String line = null;
         sb = new StringBuffer();
         while ((line = reader.readLine()) != null) {
             sb.append(line);
         }
         line = sb.toString();
         // 处理返回的字符串line
         return;
         ////
     } catch (IOException e) {
         // handle e
     } finally {
         if (conn != null)
             conn.disconnect();
     }///发送结束

addPair方法： 

 public static void addPair(StringBuffer sb, String name, String value) {
     if (value == null) {
         return;
     }
     sb.append(name);
     sb.append("=");
     sb.append(value);
     sb.append("&");
 }