http Post 請求一網絡資源返回字符串

 public static String sendPost(String url, String param) {
  PrintWriter out = null;
  BufferedReader in = null;
  String result = "";
  try {
   URL realUrl = new URL(url);
   // 打開和URL之間的連接
   URLConnection conn = realUrl.openConnection();
   // 設置通用的請求屬性
   conn.setRequestProperty("accept", "*/*");
   conn.setRequestProperty("connection", "Keep-Alive");

   // 發送POST請求必須設置如下兩行
   conn.setDoOutput(true);
   conn.setDoInput(true);
   // 獲取URLConnection對象對應的輸出流
   out = new PrintWriter(conn.getOutputStream());
   // 發送請求參數
   out.print(param);
   // flush輸出流的緩衝
   out.flush();
   // 定義BufferedReader輸入流來讀取URL的響應
   in = new BufferedReader(new InputStreamReader(conn.getInputStream(), "UTF-8"));
   String line;
   while ((line = in.readLine()) != null) {
    result += line;
   }
  } catch (Exception e) {
   System.out.println("發送 POST 請求出現異常！" + e);
   e.printStackTrace();
  }
  // 使用finally塊來關閉輸出流、輸入流
  finally {
   try {
    if (out != null) {
     out.close();
    }
    if (in != null) {
     in.close();
    }
   } catch (IOException ex) {
    ex.printStackTrace();
   }
  }
  return result;
 }