java - 定时器.schedule api : Why the timer task executes even the first time has passed

Question

我将firstTime 设置为今天15:35，然后每天一次。但是当我今天启动应用程序时，即使在 15:35 之后，它也会立即启动任务。我不想这样。

 public void scheduleTimerTask() {

        int taskStartTimeInSec = 56100;
        Timer timer = new Timer();
        Calendar today = Calendar.getInstance();
        today.set(Calendar.HOUR_OF_DAY, 0);
        today.set(Calendar.MINUTE, 0);
        today.set(Calendar.SECOND, taskStartTimeInSec);
        Date firstTime = today.getTime();
        System.out.println("firstTime is : "+ firstTime);
            timer.schedule(new Task(), firstTime,
                        1000*60*60*24);
    }

    class Task extends TimerTask{

        @Override
        public void run() {
           System.out.println("Thread Invoked at "+ new Date());

        }

    }

     public static void main(String[] args) throws ParseException {
        Test t = new Test();
        t.scheduleTimerTask();
        }


    Output : 
    firstTime is : Thu Sep 15 15:35:00 IST 2016
    Thread Invoked at Thu Sep 15 18:33:35 IST 2016

我希望如果我稍后开始(可能是 16:00)，那么今天的任务不应执行，但应该在明天 15:35 执行。因为今天已经过了15点35分的时间了。

请帮忙。

Answer 1

根据古斯塔夫的建议:

public void scheduleTimerTask() {

        int taskStartTimeInSec = 56100;
        Timer timer = new Timer();
        Calendar today = Calendar.getInstance();
        today.set(Calendar.HOUR_OF_DAY, 0);
        today.set(Calendar.MINUTE, 0);
        today.set(Calendar.SECOND, taskStartTimeInSec);
        Date firstTime = today.getTime();
        if(firstTime.before(new Date())){
            today.add(Calendar.DATE, 1);
            firstTime = today.getTime();
        }
        System.out.println("firstTime is : "+ firstTime);
            timer.schedule(new Task(), firstTime,
                        1000*60*60*24);
    }

以上效果很好。现在，如果第一次是在我添加一天之前，那么它将仅调用第二天。