问题
I have some code execution which will scheduled many jobs at different date-time. So overall I will have lot of jobs to run at specific date-time. I know that there is Spring Scheduler which will execute a job at some time period, but it does not schedule a job dynamically. I can use ActiveMQ with timed delivery or Quartz for my purpose but looking for a little suggestion. Shall I use Quartz or ActiveMQ timed/delayed delivery or something else.
There is another alternative as well in Executor service with timed execution, but if application restarts then the job will be gone I believe. Any help will be appreciated.
回答1:
While you can schedule message delivery in ActiveMQ it wasn't designed to be used as a job scheduler whereas that's exactly what Quartz was designed for.
In one of your comments you talked about wanting a "scalable solution" and ActiveMQ won't scale well with a huge number of scheduled jobs because the more messages which accumulate in the queues the worse it will perform since it will ultimately have to page those messages to disk rather than keeping them in memory. ActiveMQ, like most message brokers, was meant to hold messages for a relatively short amount of time before they are consumed. It's much different than a database which is better suited for this use-case. Quartz should scale better than ActiveMQ for a large number of jobs for this reason.
Also, the complexity of the jobs you can configure in Quartz is greater. If you go with ActiveMQ and you eventually need more functionality than it supports then that complexity will be pushed down into your application code. However, there's a fair chance could simply do what you want with Quartz since it was designed as a job scheduler.
Lastly, a database is more straight-forward to maintain than a message broker in my opinion and a database is also easy to provision in most cloud providers. I'd recommend you go with Quartz.
回答2:
You can start by using a cron-expression in order to cover the case when your application will restart. The cron-expression can be stored in the properties file. Also, when your application will be scheduled, you can restart or reschedule your job programatically by creating a new job instance with another cron-expression for example.
来源：https://stackoverflow.com/questions/56099275/scheduling-task-at-some-specific-time-in-java