java - HTTPURLConnection.getInputStream() 需要很长时间？

Question

我正在使用 HttpURLConnection 上传一个图像文件，对于一个包含所有标题的 5MB 文件大约需要 3 秒，但是当我使用 .getInputStream() 打开一个 InputStream 时，该方法需要大约 8 秒以上的时间来返回一个流与。这是一个问题，因为如果我有多个图像要上传，上传进度条似乎会提供糟糕的用户体验，每次上传之间会有相当长的停顿，所以进度条只会在上传之间停止几秒钟。我进行了一些谷歌搜索，但似乎没有其他人对此有异议？

通常我会假设服务器很慢，但鉴于上传只需要几秒钟，下载“成功”或“失败”这个词应该不是什么大问题!

这是一些代码!我最初设置错了吗？ 注意:这也在 AsyncTask 中

    ByteArrayInputStream fileInputStream = null;

    try {
        fileInputStream = new ByteArrayInputStream(dObject.Data);

    } catch (Exception e) {
        e.printStackTrace();
    }


    String lineEnd = "\r\n";
    String twoHyphens = "--";
    String boundary = "*****";
    String Tag="3rd";
    try
    {
        //------------------ CLIENT RE QUEST        
        Log.e(Tag,"Inside second Method");      

        // Open a HTTP connection to the URL    
        URL url = new URL(_urlString);
        //connectURL is a URL object
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();

        // Allow Inputs
        conn.setDoInput(true);

        // Allow Outputs
        conn.setDoOutput(true);

        // Don't use a cached copy.
        conn.setUseCaches(false);

        // Use a post method.
        conn.setRequestMethod("POST");

        conn.setRequestProperty("Connection", "Keep-Alive");

        conn.setRequestProperty("Content-Type", "multipart/form-data;boundary="+boundary);

        DataOutputStream dos = new DataOutputStream( conn.getOutputStream() );

        dos.writeBytes(twoHyphens + boundary + lineEnd);
        //dos.writeBytes("Content-Disposition: form-data; name=\"uploadedfile\";filename=\"" + _fileLocation +"\"" + lineEnd);
        dos.writeBytes("Content-Disposition: form-data; name=\"file\";filename=\"" + _fileLocation +"\"" + lineEnd);

        dos.writeBytes(lineEnd);

        Log.e(Tag,"Headers are written");

        // create a buffer of maximum size
        int bytesAvailable = fileInputStream.available();
        int maxBufferSize = 1024;
        int bufferSize = Math.min(bytesAvailable, maxBufferSize);
        byte[] buffer = new byte[bufferSize];



        // read file and write it into form...  
        int bytesRead = fileInputStream.read(buffer, 0, bufferSize);


        while (bytesRead > 0) {
            dos.write(buffer, 0, bufferSize);

            //int value = (int)(((float)((float)totalRead / (float) fileSize)) * 100);

            totalRead += bytesRead;
            //Publish the progress out to be displayed
            publishProgress(totalRead);



            bytesAvailable = fileInputStream.available();
            bufferSize = Math.min(bytesAvailable, maxBufferSize);
            bytesRead = fileInputStream.read(buffer, 0, bufferSize);
        }

        // send multipart form data necesssary after file data...
        dos.writeBytes(lineEnd);
        dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);


        // close streams
        Log.e(Tag,"File is written");
        fileInputStream.close();
        dos.flush();

        Log.e("TIME", "PRE GETINPUTSTREAM");
        InputStream is = conn.getInputStream(); 
        Log.e("TIME", "POST GETINPUTSTREAM");
        //  retrieve the response from server
        int ch;


        //Build the respose and log
        StringBuilder b =new StringBuilder();
        while( ( ch = is.read() ) != -1 ){
            b.append( (char)ch );
        }
        String s=b.toString();      
        Log.i("Response",s);
        dos.close();

        return;
    }
    catch (MalformedURLException ex)
    {
        ErrorHandler.get().e("3");
    }

    catch (IOException ioe)
    {
        ErrorHandler.get().e("2");
    }

Answer 1

Normally I would assume the server is slow, but seeing as uploading only takes a couple of seconds, downloading the word 'success' or 'fail' shouldn't really be that much of an issue!

我怀疑真的是服务器慢了或者重载了。

• 服务器可能正在对 HTTP 请求进行排队，并且一次只能并行处理少量请求。

• 或者在将包含文件的响应写入响应之前执行的某些数据库 Activity 可能存在瓶颈。

• 或者它可以在内存缓冲区中动态生成文件(慢速)，然后从缓冲区流式传输(快速)到 HTTP 响应。

• 或者像这样的其他解释......

(理论上也有可能发生了一些有趣的事情，减慢了向服务器发送请求的速度。不过我认为这不太可能。)

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您是否尝试过使用网络浏览器下载相同的文件？你在那里有同样的行为吗？