如何将数据附加到现有的Dropbox文件？

I'm accessing Dropbox API to upload and download files using Java. Now, I need to create a function which can append data to existing Dropbox file. I've a working code which first downloads a file and then uploads it with the text appended. However, is there is a better way to do this, because my code has is inefficient?I'm accessing Dropbox API to upload and downloa