Java web application : process file as File or InputStreams

Question

In my java web application I have to process excel file from user. There are two way to process this first as File second as InputStreams .

I think InputStreams will be a memory consuming thing.

Is there any possible threat if I first save user uploaded file as .xls or .xlsx and then process it?

What are the cons & pros of both approach?

Answer 1

The best way to process web application files is after uploading completely and saving in your server as a file.

Streaming file processing should be avoided because HTTP model is designed to be a Request, Response model. You shouldn't ask the Web Client wait until you finish the file processing.

Best thing to do is upload file to a directory and send the Web Client a upload success message, with possibly a link where the end user can check for the results in the future.

And having a scheduled task to process the files in the uploaded directory and post the results in the results page.

This way web application will not have unnecessary delays and scale-able.