我正在使用下面的代码以流模式上传文件（数十 MB）。为什么实际上在快速执行Util.copyStream(...);( org.apache.commons.net.io.Util) 之后，仍然在进行真正的上传（更长的时间）？如何更好地衡量该模式下的上传进度（可能）？
/**
* upload file (streaming)
* @param endpoint
*/
private void doPut(String endpoint) {
URL endpointUrl;
HttpURLConnection connection;
try {
File videoFile = new File(videoPath);
endpointUrl = new URL(endpoint);
connection = (HttpURLConnection) endpointUrl.openConnection();
connection.setRequestMethod("PUT");
connection.setRequestProperty("Content-Length", videoFile.length()+"");
connection.setRequestProperty("Content-Type", new MimetypesFileTypeMap().getContentType(videoFile));
connection.setDoOutput(true);
CopyStreamListener listener = new CopyStreamListener() {
public void bytesTransferred(long totalBytesTransferred, int bytesTransferred, long streamSize) {
System.out.printf("\r%-30S: %d / %d", "Sent", totalBytesTransferred, streamSize);
}
public void bytesTransferred(CopyStreamEvent event) {
}
};
InputStream in = new FileInputStream(videoFile);
OutputStream out = connection.getOutputStream();
System.out.println("Uploading \""+videoFile.getAbsolutePath()+"\"... ");
long c = Util.copyStream(in, out, Util.DEFAULT_COPY_BUFFER_SIZE, videoFile.length(), listener);
System.out.printf("\n%-30S: %d\n", "Bytes sent", c);
in.close();
out.close();
// at this point uploading is still taking place...
// return code
System.out.printf("\n%-30S: %d\n", "Response code", connection.getResponseCode());
} catch (Exception e) {
e.printStackTrace();
}
}