如何在android的web api中发送块文件？

Question

我正在发送大于 2mb 的文件。为了能够发送这个文件，我需要把这个文件分成每块 2mb 大小的小块 [chunks] 并按块发送。我已经将文件分成较小的块并将其发送到 Web 服务器，但问题是当我已经收到响应时，文件大小越来越大，同时逐块发送文件。但是每个块的文件大小为 2mb 所以我'我想知道为什么会发生这种情况。 预期文件长度是我发送的特定块的长度，块长度是所有已发送块的加法大小。到目前为止我得到了：

        File mFile = new File(samplefile);

        int mychunkSize = 2048 * 1024;
        final long size = mFile.length();
        final long chunks = size < mychunkSize? 1: (mFile.length() / mychunkSize);

        int chunkId = 0;
        int ordername = 0;

        int bytesRead = 0, bytesAvailable, bufferSize;


        byte[] buffer;

        int maxBufferSize = 2 * 1024 * 1024;

        if (size > maxBufferSize){ //if file size is greater than 2mb
            try {
                splitFiles = ChunkFiles.splitFile(mFile);
                String chunkedfiles="";
                int i = 0;

                for (i=0; i < splitFiles.size(); i++) {

                    chunkedfiles = splitFiles.get(i);


                    try {
                        File theChunkFiles = new File(chunkedfiles);
                        FileInputStream stream = new FileInputStream(theChunkFiles);

                        bytesAvailable = stream.available();
                        bufferSize = Math.min(bytesAvailable, maxBufferSize);
                        buffer = new byte[bufferSize];
                        int bufferlength = buffer.length;

                         // read file and write it into form...
                         bytesRead = stream.read(buffer, 0, bufferSize);
                        ordername++;

                        String lineEnd = "\r\n";
                        String twoHyphens = "--";
                        String boundary =  "-------------------------acebdf13572468";// random data


                         String param3 = mFile.getName();
                         String param4 = samplefile;
                         String chunkFileName = theChunkFiles.getName();

                             URL url = new URL(urlString);

                             // Open a HTTP connection to the URL
                             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");

                             String encoded = Base64.encodeToString((_username+":"+_password).getBytes(),Base64.NO_WRAP); 
                             conn.setRequestProperty("Authorization", "Basic "+encoded);
                             conn.setRequestProperty("Connection", "Keep-Alive");
                             conn.setRequestProperty("Content-Type", "multipart/form-data;boundary="+boundary);

                             conn.setChunkedStreamingMode(0);


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

                             dos.writeBytes(twoHyphens + boundary + lineEnd);


                            dos.writeBytes("Content-Disposition: form-data; name=\"fieldNameHere\";filename=\"" + chunkFileName + "\"" + lineEnd); // filename is the Name of the File to be uploaded
                            dos.writeBytes("Content-Type: application/octet-stream" + lineEnd);
                            dos.writeBytes(lineEnd);

                            while (bytesRead > 0) {
                                dos.write(buffer, 0, bufferSize);
                                bufferSize = Math.min(bytesAvailable, maxBufferSize);
                                bytesRead = stream.read(buffer, 0, bufferSize);
                            }


                                var = bufferSize;

                            dos.writeBytes(lineEnd);
                            dos.writeBytes(twoHyphens + boundary + lineEnd);


                            // Send parameter #chunks
                            dos.writeBytes("Content-Disposition: form-data; name=\"chunk\"" + lineEnd);

                            dos.writeBytes(lineEnd);
                            dos.writeBytes(chunkId + lineEnd);
                            dos.writeBytes(twoHyphens + boundary + lineEnd);


                            // Send parameter #name
                            dos.writeBytes("Content-Disposition: form-data; name=\"name\"" + lineEnd);

                            dos.writeBytes(lineEnd);
                            dos.writeBytes("ForFiddlerTest19VIDEO_20130711_151315_-2073548175.mp4" + lineEnd);



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

                            chunkId++;


                             is = conn.getInputStream();

                          // retrieve the response from server
                          int ch;

                          StringBuffer b =new StringBuffer();
                          while( ( ch = is.read() ) != -1 ){ b.append( (char)ch ); }
                          String s=b.toString();
                          Log.i("Response",s);
                         //stream.close();
                         is.close();
                         dos.close();



                    } catch (MalformedURLException ex) {
                        System.out.println("From CLIENT REQUEST:" + ex);
                    }catch (IOException ioe) {
                        System.out.println("From CLIENT REQUEST:" + ioe);
                    }catch (Exception e) {
                        Log.e("From CLIENT REQUEST:", e.toString());
                    }



                }
                dos.flush();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

这是我得到的示例响应：

{"Filename":"ForFiddlerTest19VIDEO_20130711_151315_-2073548175.mp4","ChunkId":2,"ChunkLength":2097152,"FileLength":6291456}

文件长度增加而不是块长度

Answer 1

"ChunkLength":2097152,"FileLength":6291456

块长度是恒定的 - 2 MB 并且服务器返回的文件长度正在增加，因为服务器可能会将块连接到单个文件中 - 在最终文件的末尾附加每个新块，因此对于每个请求，您都会获得新的、更大的文件长度作为响应而块长度是恒定的。