尝试写入在线文本文件时获取响应代码404

Question

我正在尝试将数据保存到一个尚未在线存在的文本文件中，但我的urlConnection.getResponseCode()正在返回404.我可以从具有相似网址的文件中读取，所以我很确定网址是是的，但我以前从未写过在线文件。

private class SaveFile extends AsyncTask<String, Void, String> {
        private String scheme = "http";
        private String authority = "172.16.0.45";
        private String path1 = "PrivateFile";
        private String path2 = "SavedInstances";
        protected void onPreExecute() {

        }

        protected String doInBackground(String...params) {
            String result = null;
            String filename = params[0] + ".txt";
            String location = params[1];
            OutputStream outStream = null;
            HttpURLConnection urlConnection = null;
            try {
                // Save online as opposed to internal storage
                if (location.equals("on")) {
                    Uri.Builder builder = new Uri.Builder();
                    builder.scheme(scheme);
                    builder.authority(authority);
                    builder.appendPath(path1);
                    builder.appendPath(path2);
                    builder.appendPath(filename);
                    String _url = builder.build().toString();
                    URL url = new URL(_url);
                    urlConnection = (HttpURLConnection) url.openConnection();
                    urlConnection.setDoOutput(true);
                    urlConnection.setRequestMethod("POST");
                    if (urlConnection.getResponseCode() != 200) // Runs as true
                        throw new IOException(Integer.toString(urlConnection.getResponseCode()));
                    else {
                        outStream = urlConnection.getOutputStream();
                    }
                } else if (location.equals("in")) {// Saving to internal
                    File file = new File(getFilesDir(), filename);
                    outStream = new FileOutputStream(file);
                }
                // Writing the file
                PrintWriter writer = new PrintWriter(outStream);
                writer.println(utils.size());
                writer.println(trans.size());
                writer.println(cables.size());
                for (int i = 0; i < utils.size(); i++)
                    writer.println(utils.get(i).getValues());
                for (int i = 0; i < trans.size(); i++)
                    writer.println(trans.get(i).getValues());
                for (int i = 0; i < cables.size(); i++)
                    writer.println(cables.get(i).getValues());
                writer.close();
                outStream.close();
                if (urlConnection != null)
                    urlConnection.disconnect();
                result = "Save Successful";
            } catch (FileNotFoundException e) {
                System.out.println(e.getMessage());
            } catch (MalformedURLException e) {
                System.out.println(e.getMessage());
            } catch (IOException e) {
                result = e.getMessage();// 404
                System.out.println(e.getMessage());
            }
            return result;
        }

        protected void onPostExecute(String result) {
            Toast.makeText(getApplicationContext(),result,Toast.LENGTH_SHORT).show();
        }
    }

当我使用getResponseMessage（）发送异常时，消息“未找到”。为了让这种联系起作用，我错过了什么？