雖然存在文件，但找不到AsyncTask返回文件

Question

我在Android Studio中遇到AsyncTask類的問題。當文件確實存在時，它會一直給我發送「找不到文件」的消息。以下是我的代碼片段：

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(); 
     } 
    } 
} 

僅供參考，我有很多類似於此的其他AsyncTask類，他們工作得很好。我只是爲這個班級出錯，我不知道爲什麼。 有誰知道如何真正解決這個問題？

Answer 1

我發現問題實際上是服務器端。服務器的PHP語言版本很低，所以PHP腳本無法在服務器上正常運行。然而，在轉移到另一臺PHP版本更高的服務器後，腳本工作正常。問題解決了。

然而，非常不幸的是，Android Studio給出了誤導性的錯誤信息。它說文件沒有找到，而文件恰好在那裏。它應該給出更合適的錯誤信息，例如：PHP錯誤或者其他的東西。