Finishing a HttpServletResponse but continue processing

Question

I have a situation that seems to fit the Async Servlet 3.0 / Comet situation but all I need to do is return a 200 response code (or other) after accepting the incoming parameter

Answer 1

On possibility for your servlet to accept a request for processing in the background, is for the servlet to hand off processing to a separate thread which then executes in the background.

Using Spring, you can invoke a separate Thread using the a TaskExecutor. The advantage of using spring over standard JDK 5 java.util.concurrent.Executor is that if you're on application servers that need to use managed threads (IBM websphere or Oracle weblogic), you can use the WorkManagerTaskExecutor to hook into the CommonJ work managers.

Another alternative would be to move the long query logic into a Message Driven Bean or Message Driven POJO (Spring JMS can help here) and let the servlet simply post a message on a JMS queue. That would have the advantage that should the load on your web container become too great because of your long running query, you could easily move the MDB onto a different (dedicated) system.