GetInputStream进入无限循环

Question

我对Java中的网络编程非常陌生。我正在尝试将.img文件上传到Netgear路由器以更新固件。但是在第con.getInputStream()行，我得到了该计划的死亡旋转轮，经过几个小时的等待后没有任何回报。请帮忙。

private void uploadFile(String filePath) {
    String end = "\r\n";
    String twoHyphens = "--";
    String boundary = "WebKitFormBoundaryBZGOKkNua1gVYHFA";
    try {
        URL mUrl = new URL(url);
        HttpURLConnection con = (HttpURLConnection) mUrl.openConnection();
       con.setDoInput(true);
       con.setDoOutput(true);
       con.setUseCaches(false);
       con.setRequestMethod("POST");
       con.setRequestProperty("Upgrade-Insecure-Requests", "1");
       con.setRequestProperty("Authorization",
     "Basic YWRtaW46cGFzc3dvcmQ=");
       con.setRequestProperty("Host", "www.routerlogin.net");
       con.setRequestProperty("Origin", "http://www.routerlogin.net");
       con.setRequestProperty("Referer",
     "http://www.routerlogin.net/UPG_upgrade.htm");
       con.setRequestProperty("Connection", "Keep-Alive");
       con.setRequestProperty("Charset", "UTF-8");
       con.setRequestProperty("Content-Type",
     "multipart/form-data;boundary=" + boundary);
       DataOutputStream ds = new DataOutputStream(con.getOutputStream());
       ds.writeBytes(twoHyphens + boundary + end);
       ds.writeBytes("Content-Disposition: form-data; "
     + "name=\"mtenFWUpload\";filename=\"" + fileName + "\""
     + end + "Content-Type: application/octet-stream");
       ds.writeBytes(end);
       FileInputStream fStream = new FileInputStream(filePath);
       int bufferSize = 1024;
       byte[] buffer = new byte[bufferSize];
       int length = -1;
       while ((length = fStream.read(buffer)) != -1) {
        ds.write(buffer, 0, length);
       }
       ds.writeBytes(end);
       ds.writeBytes(twoHyphens + boundary + end);
       ds.writeBytes("Content-Disposition: form-data; "
     + "name=\"Upgrade\"" + end);
       ds.writeBytes("ÉÏ´«");
       ds.writeBytes(end);
       ds.writeBytes(twoHyphens + boundary + end);
       ds.writeBytes("Content-Disposition: form-data; " + "name=\"SID\""
     + end);
       ds.writeBytes("");
       ds.writeBytes(end);
       ds.writeBytes(twoHyphens + boundary + twoHyphens + end);
       fStream.close();
       ds.flush();
       InputStream is = con.getInputStream();
       int ch;
       StringBuffer b = new StringBuffer();
       while ((ch = is.read()) != -1) {
       b.append((char) ch);
       }
       ds.close();
       Thread.sleep(2000);
       getUpdateKey();
  } catch (Exception e) {
       e.printStackTrace();
  }
}