What happen even many request comes through one spring controller? Does Spring pipe it? How about add @Transactinal on controller? Is it have a benefit to use on controller layer?
Basically you are asking 2 questions
@Transactional
to a handler.Multiple concurrent requests are handled concurrently. Each thread has its own callstack and location in memory and doesn't share a thing. In general no problem (used Spring MVC in very high concurrent applications) unless you start, for some reason, sharing state in your singleton, or forget to clean-up ThreadLocals
.
Adding @Transactional is something bad, IMHO. The transactional layer is NOT your web but your service layer. So don't add transactions to your web but add them to your service layer.