execute method periodically when I start server in j2ee

Question

I need to execute method periodically when I start server, I'm using Tomcat v6.0 Server, and as a frameworks, I use hibernate, JSF, Primefaces and spring. Should I add something in web.xml ?

Answer 1

There are several solutions, you can achive your need by one of this way.

Assume your method is a Dispatch task you scheduled to run once in some interval sec

Keep your task in separate class and schedule it after your context sucessfully initilized

ScheduledExecutorService scheduledExcecutor = Executors.newScheduledThreadPool(3);
scheduledExcecutor.scheduleWithFixedDelay(yourTaskInstance, 0,
                                           sleepInterval, TimeUnit.MILLISECONDS);

You can schedulewith Fixed Rate also,check ScheduledExecutorService document

Shutdown it gracefully when your server is down.

Answer 2

Based on your application environment, you can add startup hook with any of the below ways.

• Spring

  You can implement Lifecycle or SmartLifeCycle interface for application context's startup and shutdown phases.

• Tomcat

  You can add listener by implementing LifecycleListener

• Generic

  1. ServletContextListener
  2. Configuring servlet to load-on-startup.

Afterwards, you can add ScheduledThreadPoolExecutor to execute tasks periodically.