Android getContentLength返回-1但在瀏覽器中返回文件大小，怎麼樣？

Question

我試圖從使用Android的URL找到文件大小，但我得到getContentLength（）：-1，但如果我將在任何瀏覽器中打開url，那麼瀏覽器可以計算出文件大小，因爲瀏覽器是也是客戶端應用程序。

mycode的：

try { 
     URL url = new URL("https://www.dropbox.com/s/mk75lhvi96gkc00/match.flv?dl=0"); 
     connection = (HttpURLConnection) url.openConnection(); 
     connection.setRequestMethod("GET"); 
     connection.connect(); 

     // expect HTTP 200 OK, so we don't mistakenly save error report 
     // instead of the file 
     if (connection.getResponseCode() != HttpURLConnection.HTTP_OK) { 
      return "Server returned HTTP " + connection.getResponseCode() 
        + " " + connection.getResponseMessage(); 
     } 

     // this will be useful to display download percentage 
     // might be -1: server did not report the length 
     int fileLength = connection.getContentLength(); 

     //fileLength : -1; 

    } catch (Exception e) { 
     return e.toString(); 
    } finally { 
     try { 
      if (output != null) 
       output.close(); 
      if (input != null) 
       input.close(); 
     } catch (IOException ignored) { 
     } 

     if (connection != null) 
      connection.disconnect(); 
    } 

這是我的Android上面的代碼，我得到-1作爲文件的長度，但是相同的URL文件的大小可以通過瀏覽器容易計算出來。

請給我一些解決方案。

Answer 1

此代碼工作正常，我：基於this answer

Answer 2

嘗試

public int getFileSizeFromURL(String urlPath) { 
    int fileSize = 0; 
    try { 
     URL url = new URL(urlPath); 
     HttpURLConnection connection = (HttpURLConnection)  url.openConnection(); 
     connection.setRequestMethod("GET"); 
     connection.connect(); 
     fileSize = connection.getContentLength(); 
     connection.disconnect(); 
    } catch (Exception e) { 
     e.printStackTrace(); 
    } 
    return fileSize; 
} 

代碼改變從

"https://www.dropbox.com/s/mk75lhvi96gkc00/match.flv?dl=0" 

鏈接

"https://www.dropbox.com/s/mk75lhvi96gkc00/match.flv?dl=1"