将Java任务安排在指定时间内

Question

我希望能够在Java中的特定时间安排任务。我知道ExecutorService能够在指定的延迟后定期调度，但我更关注的是一天中的某个时间，而不是某个持续时间之后。

比方说，有没有办法让Runnable在2:00执行，或者我需要计算从现在到2:00的时间，然后调度runnable在该延迟之后执行？

Answer 1

你会想要Quartz的。

Answer 2

您也可以使用spring注解。

@Scheduled(cron="*/5 * * * * MON-FRI")
public void doSomething() {
// something that should execute on weekdays only
}

http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/scheduling.html

Answer 3

这就是我用java7SE解决这个问题的方法：

    timer = new Timer("Timer", true);
    Calendar cr = Calendar.getInstance(TimeZone.getTimeZone("GMT"));
    cr.setTimeInMillis(System.currentTimeMillis());
    long day = TimeUnit.DAYS.toMillis(1);
    //Pay attention - Calendar.HOUR_OF_DAY for 24h day model 
    //(Calendar.HOUR is 12h model, with p.m. a.m. )
    cr.set(Calendar.HOUR_OF_DAY, it.getHours());
    cr.set(Calendar.MINUTE, it.getMinutes());
    long delay = cr.getTimeInMillis() - System.currentTimeMillis();
    //insurance for case then time of task is before time of schedule
    long adjustedDelay = (delay > 0 ? delay : day + delay);
    timer.scheduleAtFixedRate(new StartReportTimerTask(it), adjustedDelay, day);
    //you can use this schedule instead is sure your time is after current time
    //timer.scheduleAtFixedRate(new StartReportTimerTask(it), cr.getTime(), day);

它碰巧比我想象的要难做得多。