虽然存在文件，但找不到AsyncTask返回文件

Question

我在Android Studio中遇到AsyncTask类的问题。当文件确实存在时，它会一直给我发送“找不到文件”的消息。以下是我的代码片段：

public class PhpInsertProduct extends AsyncTask<String, Void, String> { 

    private BufferedReader bufferedReader; 
    private BufferedWriter bufferedWriter; 
    private Context context; 
    private HttpURLConnection httpURLConnection; 
    private OutputStream outputStream; 
    private ProgressDialog progressDialog; 
    private Snackbar snackbar; 
    private static String PHP_INSERT_PRODUCT = "http://www.example.com/phpexample.php"; //this file exists but Android Studio keeps giving me "file not found" error for this file 
    private String inputLine, query, result, categoryName, name, price, image, saleStartTime, saleDuration, salePrice, desc, createdAt, createdBy; 
    private String[] ftpImagePaths; 
    private StringBuffer response; 
    private TextView tvSnackbarTextView; 
    private Uri.Builder uriBuilder; 
    private URL url; 
    private View snackbarView, view; 

    public PhpInsertProduct(Context context, View view, ProgressDialog progressDialog, String categoryName, String[] ftpImagePaths) 
    { 
     this.context = context; 
     this.view = view; 
     this.progressDialog = progressDialog; 
     this.categoryName = categoryName; 
     this.ftpImagePaths = ftpImagePaths; 
    } 

    @Override 
    protected String doInBackground(String... args) 
    { 
     name = args[0]; 
     price = args[1]; 
     image = args[2]; 
     saleStartTime = args[3]; 
     saleDuration = args[4]; 
     salePrice = args[5]; 
     desc = args[6]; 
     createdAt = args[7]; 
     createdBy = args[8]; 
     try 
     { 
      url = new URL(PHP_INSERT_PRODUCT); 
      httpURLConnection = (HttpURLConnection) url.openConnection(); 
      httpURLConnection.setDoInput(true); 
      httpURLConnection.setDoOutput(true); 
      httpURLConnection.setRequestMethod("POST"); 
      httpURLConnection.addRequestProperty("Accept-Encoding", "UTF-8"); 
      uriBuilder = new Uri.Builder() 
        .appendQueryParameter("name", name) 
        .appendQueryParameter("price", price) 
        .appendQueryParameter("image", image) 
        .appendQueryParameter("saleStartTime", saleStartTime) 
        .appendQueryParameter("saleDuration", saleDuration) 
        .appendQueryParameter("salePrice", salePrice) 
        .appendQueryParameter("desc", desc) 
        .appendQueryParameter("createdAt", createdAt) 
        .appendQueryParameter("createdBy", createdBy); 
      query = uriBuilder.build().getEncodedQuery(); 
      outputStream = httpURLConnection.getOutputStream(); 
      bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8")); 
      bufferedWriter.write(query); 
      bufferedWriter.flush(); 
      bufferedWriter.close(); 
      outputStream.close(); 
      httpURLConnection.connect(); 
      bufferedReader = new BufferedReader(new InputStreamReader(httpURLConnection.getInputStream())); //this is the line that triggers the error 
      response = new StringBuffer(); 
      while ((inputLine = bufferedReader.readLine()) != null) response.append(inputLine); 
      bufferedReader.close(); 
      result = response.toString(); 
      httpURLConnection.disconnect(); 
     } 
     catch (Exception e) 
     { 
      e.printStackTrace(); 
      return e.getMessage(); 
     } 
     return result; 
    } 

    @Override 
    protected void onPostExecute(String result) 
    { 
     if(result.isEmpty()) new PhpGetItemId(context, view, progressDialog, categoryName, ftpImagePaths, null, createdAt, createdBy).executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, name); 
     else 
     { 
      progressDialog.dismiss(); 
      FragmentAddProducts.fragmentAddProducts.setSaveInProgress(false); 
      snackbar = Snackbar.make(view, context.getResources().getString(R.string.error_saving_product), Snackbar.LENGTH_LONG); 
      snackbarView = snackbar.getView(); 
      snackbarView.setBackgroundColor(Color.parseColor("#00DDFF")); 
      tvSnackbarTextView = (TextView) snackbarView.findViewById(android.support.design.R.id.snackbar_text); 
      tvSnackbarTextView.setTextColor(Color.parseColor("#FF3333")); 
      snackbar.show(); 
     } 
    } 
} 

仅供参考，我有很多类似于此的其他AsyncTask类，他们工作得很好。我只是为这个班级出错，我不知道为什么。 有谁知道如何真正解决这个问题？

Answer 1

我发现问题实际上是服务器端。服务器的PHP语言版本很低，所以PHP脚本无法在服务器上正常运行。然而，在转移到另一台PHP版本更高的服务器后，脚本工作正常。问题解决了。

然而，非常不幸的是，Android Studio给出了误导性的错误信息。它说文件没有找到，而文件恰好在那里。它应该给出更合适的错误信息，例如：PHP错误或者其他的东西。