src/org/nutz/lang/Tasks.java
public static void scheduleAtFixedTime(final Runnable task, Date startTime) {
        final Timer timer = new Timer();
        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                taskScheduler.execute(task);
                timer.cancel();
                timerList.remove(timer);
            }
        }, startTime);
        timerList.add(timer);
    }
public static void scheduleAtFixedTime(final Runnable task, Date startTime) {
        final Timer timer = new Timer();
        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                taskScheduler.execute(task);
                timer.cancel();
                timerList.remove(timer);
            }
        }, startTime);
        timerList.add(timer);
    }
在指定的时间点启动任务只运行一次
@param task 具体待执行的任务
@param startTime 运行的时间点