servlet中用流的方式传输文件

servlet服务端接收:

FileOutputStream fileOutputStream = FileUtils.openOutputStream(new File(resultFile));
InputStream requestInputStream = request.getInputStream();
IOUtils.copy(requestInputStream, fileOutputStream);

 客户端上传代码：

URL url = new URL(urlStr);
HttpURLConnection httpUrlConnection = (HttpURLConnection) url.openConnection();
httpUrlConnection.setDoOutput(true);
httpUrlConnection.setDoInput(true);
httpUrlConnection.setUseCaches(false);
httpUrlConnection.setRequestMethod("POST"); 
httpUrlConnection.setRequestProperty("Content-type", "text/html");
httpUrlConnection.setRequestProperty("moduleName", moduleName);
httpUrlConnection.setRequestProperty("tdate", tdate);
httpUrlConnection.connect();
httpOutputStream = httpUrlConnection.getOutputStream();
IOUtils.copy(inputStream, httpOutputStream);

试了一下，上面这个可以用servlet实现文件传输。
想问一下有没有大神知道，这样的方式，文件传输的量能有多大，原理是什么？