spring 如何管理 session？

Question

I have a small springboot app which gets a file uploaded, do some work on it. and returns back another file. I have implemented frontend using reactJS. There is a static variable which holds the name of file. It works fine with one file. But, when I throw multiple files at it, the file which gets uploaded at last overrides the static variable for each operation. I'm new to spring and I have read each request is handled in a different container. I'm not able to understand how one 'container' is creating ruckus in another 'container'?

Answer 1

Your understanding about "requests in different containers" is completely erroneous. Spring doesn't handle sessions directly; the embedded Servlet engine (usually Tomcat) does, unless you specifically include something like Spring Session that positively takes over the handling.

In either case, though, this has nothing to do with sessions and everything to do with shared state (whether static or via a singleton Spring bean). It would be absurdly expensive to spin up a completely new copy of the application for each request, and even if you did you'd still lose your state between requests. You need to (less ideal) store the variable in a session attribute or (best) return some sort of ID with an HTTP 202 Accepted status and keep an internal table so that it can be checked on later.