Is it possible to run a cron job in a web applicat

Question

In a java web application (servlets/spring mvc), using tomcat, is it possible to run a cron job type service?

e.g. every 15 minutes, purge the log database.

Can you do this in a way that is container independent, or it has to be run using tomcat or some other container?

Please specify if the method is guaranteed to run at a specific time or one that runs every 15 minutes, but may be reset etc. if the application recycles (that's how it is in .net if you use timers)

Answer 1

If you're using Spring, you can use the built-in Quartz or Timer hooks. See http://static.springsource.org/spring/docs/2.5.x/reference/scheduling.html

Answer 2

It will be container-specific. You can do it in Java with Quartz or just using Java's scheduling concurrent utils (ScheduledExecutorService) or as an OS-level cron job.

Every 15 minutes seems extreme. Generally I'd also advise you only to truncate/delete log files that are no longer being written to (and they're generally rolled over overnight).

Answer 3

Jobs are batch oriented. Either by manual trigger or cron-style (as you seem to want).

Still I don't get your relation between webapp and cron-style job? The only webapp use-case I could think of is, that you want to have a HTTP endpoint to trigger a job (but this opposes your statement about being 'cron-style').

Generally use a dedicated framework, which solves the problem-area 'batch-jobs'. I can recommend quartz.

Answer 4

As documented in Chapter 23. Scheduling and Thread Pooling, Spring has scheduling support through integration classes for the Timer and the Quartz Scheduler (http://www.quartz-scheduler.org/). For simple needs, I'd recommend to go with the JDK Timer.

Note that Java schedulers are usually used to trigger Java business oriented jobs. For sysadmin tasks (like the example you gave), you should really prefer cron and traditional admin tools (bash, etc).