向指定Url發送post請求

/**
   * 向指定 URL 發送POST方法的請求
   *
   * @param url 發送請求的 URL
   * @param param 請求參數,json格式，請求參數應該是{name:value1,name2:value2}的形式。
   * @return 所代表遠程資源的響應結果
   * @throws IOException
   */
  public static String sendPost(String url, String param) {
    PrintWriter out = null;
    BufferedReader in = null;
    StringBuilder result = new StringBuilder();
    URLConnection conn = null;
    try {
      URL realUrl = new URL(url);
      // 打開和URL之間的連接
      conn = realUrl.openConnection();
      // 設置通用的請求屬性
      conn.setRequestProperty("accept", "*/*");
      conn.setRequestProperty("Accept-Charset", "UTF-8");
      conn.setRequestProperty("contentType", "UTF-8");
      conn.setRequestProperty("Accept-Language", Locale.getDefault().toString());
      conn.setRequestProperty("Accept",
          "image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/x-shockwave-flash, application/xaml+xml, application/vnd.ms-xpsdocument, application/x-ms-xbap, application/x-ms-application, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*");
      conn.setRequestProperty("Content-Type", "application/json;charset=UTF-8");
      // 發送POST請求必須設置如下兩行
      conn.setConnectTimeout(30000);
      conn.setReadTimeout(120000);
      conn.setDoOutput(true);
      conn.setDoInput(true);
      // 獲取URLConnection對象對應的輸出流
      out = new PrintWriter(new OutputStreamWriter(conn.getOutputStream(), "UTF-8"));
      // out = new PrintWriter(conn.getOutputStream());
      // 發送請求參數
      out.print(param);
      // flush輸出流的緩沖
      out.flush();
      // 定義BufferedReader輸入流來讀取URL的響應
      InputStream stream = conn.getInputStream();
      in = new BufferedReader(new InputStreamReader(stream, "UTF-8"));
      String line;
      while ((line = in.readLine()) != null) {
        result.append(line);
      }
    } catch (Exception e) {
      e.printStackTrace();
      try {
        in = new BufferedReader(new InputStreamReader(((HttpURLConnection) conn).getErrorStream(), "UTF-8"));
        String line;
        while ((line = in.readLine()) != null) {
          result.append(line);
        }
      } catch (IOException e1) {
        e1.printStackTrace();
      }

    } finally {
      try {
        if (out != null) {
          out.close();
        }
        if (in != null) {
          in.close();
        }
      } catch (IOException ex) {
        ex.printStackTrace();
      }
    }
    return result.toString();
  }