Web service and creating a temporary output file.

Question

I want an axis web service to receive requests, write the response to a file and send the address or URL of this file back to the web service client. Then, the client can stream the file as bytes from the URL it received.

Now, where should the web service write this file? The web service is packaged as a war. I understand that anything outside the WEB-INF folder is accessible directly from the browser, so is that where I should write the file? Will this solution necessarily be application server specific?