Timer timer = new Timer();
        TimerTask timerTask = new TimerTask() {
            @Override
            public void run() {
                // TODO Auto-generated method stub
            }
        };
        //延遲1秒后開始調(diào)度任務(wù)
        timer.schedule(timerTask, 1000);
        //延遲1秒，固定延遲1秒周期性調(diào)度
        timer.schedule(timerTask, 1000, 1000);
        //延遲1秒，固定速率1秒周期性調(diào)度
        timer.scheduleAtFixedRate(timerTask, 1000, 1000);

/**
     * The timer task queue.  This data structure is shared with the timer
     * thread.  The timer produces tasks, via its various schedule calls,
     * and the timer thread consumes, executing timer tasks as appropriate,
     * and removing them from the queue when they're obsolete.
     */
    private final TaskQueue queue = new TaskQueue();　　　　　　　　　　//調(diào)度隊(duì)列
    /**
     * The timer thread.
     */
    private final TimerThread thread = new TimerThread(queue);　　　　//輪詢線程

private TimerTask[] queue = new TimerTask[128];
    //增加調(diào)度任務(wù)時(shí)，如果長度超過隊(duì)列長度，則擴(kuò)容為原先2倍
    void add(TimerTask task) {
        // Grow backing store if necessary
        if (size + 1 == queue.length)
            queue = Arrays.copyOf(queue, 2*queue.length);
        queue[++size] = task;
        fixUp(size);
    }
    private void sched(TimerTask task, long time, long period) {
        if (time < 0)
            throw new IllegalArgumentException("Illegal execution time.");
        // Constrain value of period sufficiently to prevent numeric
        // overflow while still being effectively infinitely large.
        if (Math.abs(period) > (Long.MAX_VALUE >> 1))
            period >>= 1;
        synchronized(queue) {　　　　　　　　　　//任意線程均可修改調(diào)度隊(duì)列，因此會導(dǎo)致現(xiàn)場不安全，所以這邊用同步。
            if (!thread.newTasksMayBeScheduled)
                throw new IllegalStateException("Timer already cancelled.");
            synchronized(task.lock) {　　　　//調(diào)度隊(duì)列增加任務(wù)時(shí)，其他線程也可以修改該任務(wù)，導(dǎo)致線程不安全，所以這邊用同步
                if (task.state != TimerTask.VIRGIN)
                    throw new IllegalStateException(
                        "Task already scheduled or cancelled");
                task.nextExecutionTime = time;
                task.period = period;
                task.state = TimerTask.SCHEDULED;
            }
            queue.add(task);　　　　　　　　//增加到調(diào)度隊(duì)列中
            if (queue.getMin() == task)　　
                queue.notify();
        }
    }

　/**
     * The state of this task, chosen from the constants below.
     */
    int state = VIRGIN;　　　　　　　　　　//默認(rèn)狀態(tài)是VIRGIN
    /**
     * This task has not yet been scheduled.
     */
    static final int VIRGIN = 0;
    /**
     * This task is scheduled for execution.  If it is a non-repeating task,
     * it has not yet been executed.
     */
    static final int SCHEDULED   = 1;
    /**
     * This non-repeating task has already executed (or is currently
     * executing) and has not been cancelled.
     */
    static final int EXECUTED    = 2;
    /**
     * This task has been cancelled (with a call to TimerTask.cancel).
     */
    static final int CANCELLED   = 3;
　　/**
     * Next execution time for this task in the format returned by
     * System.currentTimeMillis, assuming this task is scheduled for execution.
     * For repeating tasks, this field is updated prior to each task execution.
     */
    long nextExecutionTime;　　　　　　　　//下次調(diào)度執(zhí)行時(shí)間
    /**
     * Period in milliseconds for repeating tasks.  A positive value indicates
     * fixed-rate execution.  A negative value indicates fixed-delay execution.
     * A value of 0 indicates a non-repeating task.
     */
    long period = 0;　　　　　　　　　　　　//間隔

    public void schedule(TimerTask task, long delay) {
        if (delay < 0)
            throw new IllegalArgumentException("Negative delay.");
        sched(task, System.currentTimeMillis()+delay, 0);
    }
    public void schedule(TimerTask task, long delay, long period) {
        if (delay < 0)
            throw new IllegalArgumentException("Negative delay.");
        if (period <= 0)
            throw new IllegalArgumentException("Non-positive period.");
        sched(task, System.currentTimeMillis()+delay, -period);
    }
    public void scheduleAtFixedRate(TimerTask task, long delay, long period) {
        if (delay < 0)
            throw new IllegalArgumentException("Negative delay.");
        if (period <= 0)
            throw new IllegalArgumentException("Non-positive period.");
        sched(task, System.currentTimeMillis()+delay, period);
    }

    public void cancel() {
        synchronized(queue) {
            thread.newTasksMayBeScheduled = false;
            queue.clear();
            queue.notify();  // In case queue was already empty.
        }
    }
    private void sched(TimerTask task, long time, long period) {
        if (time < 0)
            throw new IllegalArgumentException("Illegal execution time.");
        // Constrain value of period sufficiently to prevent numeric
        // overflow while still being effectively infinitely large.
        if (Math.abs(period) > (Long.MAX_VALUE >> 1))
            period >>= 1;
        synchronized(queue) {
            if (!thread.newTasksMayBeScheduled)
                throw new IllegalStateException("Timer already cancelled.");
            synchronized(task.lock) {
                if (task.state != TimerTask.VIRGIN)
                    throw new IllegalStateException(
                        "Task already scheduled or cancelled");
                task.nextExecutionTime = time;
                task.period = period;
                task.state = TimerTask.SCHEDULED;
            }
            queue.add(task);
            if (queue.getMin() == task)
                queue.notify();
        }
    }
    private void mainLoop() {
        while (true) {
            try {
                TimerTask task;
                boolean taskFired;
                synchronized(queue) {
                    // Wait for queue to become non-empty
                    while (queue.isEmpty() && newTasksMayBeScheduled)
                        queue.wait();
                    if (queue.isEmpty())
                        break; // Queue is empty and will forever remain; die
                    // Queue nonempty; look at first evt and do the right thing
                    long currentTime, executionTime;
                    task = queue.getMin();
                    synchronized(task.lock) {
                        if (task.state == TimerTask.CANCELLED) {
                            queue.removeMin();
                            continue;  // No action required, poll queue again
                        }
                        currentTime = System.currentTimeMillis();
                        executionTime = task.nextExecutionTime;
                        if (taskFired = (executionTime<=currentTime)) {
                            if (task.period == 0) { // Non-repeating, remove
                                queue.removeMin();
                                task.state = TimerTask.EXECUTED;
                            } else { // Repeating task, reschedule
                                queue.rescheduleMin(
                                  task.period<0 ? currentTime   - task.period
                                                : executionTime + task.period);
                            }
                        }
                    }
                    if (!taskFired) // Task hasn't yet fired; wait
                        queue.wait(executionTime - currentTime);
                }
                if (taskFired)  // Task fired; run it, holding no locks
                    task.run();
            } catch(InterruptedException e) {
            }
        }
    }

public int purge() {
         int result = 0;
         synchronized(queue) {
             for (int i = queue.size(); i > 0; i--) {
                 if (queue.get(i).state == TimerTask.CANCELLED) {
                     queue.quickRemove(i);
                     result++;
                 }
             }
             if (result != 0)
                 queue.heapify();
         }
         return result;
     }

private void mainLoop() {
        while (true) {
            try {
                TimerTask task;
                boolean taskFired;
                synchronized(queue) {
                    // Wait for queue to become non-empty
                    while (queue.isEmpty() && newTasksMayBeScheduled)
                        queue.wait();
                    if (queue.isEmpty())
                        break; // Queue is empty and will forever remain; die
                    // Queue nonempty; look at first evt and do the right thing
                    long currentTime, executionTime;
                    task = queue.getMin();
                    synchronized(task.lock) {
                        if (task.state == TimerTask.CANCELLED) {
                            queue.removeMin();
                            continue;  // No action required, poll queue again
                        }
                        currentTime = System.currentTimeMillis();
                        executionTime = task.nextExecutionTime;
                        if (taskFired = (executionTime<=currentTime)) {
                            if (task.period == 0) { // Non-repeating, remove
                                queue.removeMin();
                                task.state = TimerTask.EXECUTED;
                            } else { // Repeating task, reschedule
                                queue.rescheduleMin(
                                  task.period<0 ? currentTime   - task.period
                                                : executionTime + task.period);
                            }
                        }
                    }
                    if (!taskFired) // Task hasn't yet fired; wait
                        queue.wait(executionTime - currentTime);
                }
                if (taskFired)  // Task fired; run it, holding no locks
                    task.run();
            } catch(InterruptedException e) {
            }
        }
    }
    private void sched(TimerTask task, long time, long period) {
        if (time < 0)
            throw new IllegalArgumentException("Illegal execution time.");
        // Constrain value of period sufficiently to prevent numeric
        // overflow while still being effectively infinitely large.
        if (Math.abs(period) > (Long.MAX_VALUE >> 1))
            period >>= 1;
        synchronized(queue) {
            if (!thread.newTasksMayBeScheduled)
                throw new IllegalStateException("Timer already cancelled.");
            synchronized(task.lock) {
                if (task.state != TimerTask.VIRGIN)
                    throw new IllegalStateException(
                        "Task already scheduled or cancelled");
                task.nextExecutionTime = time;
                task.period = period;
                task.state = TimerTask.SCHEDULED;
            }
            queue.add(task);
            if (queue.getMin() == task)
                queue.notify();
        }
    }

    public void cancel() {
        synchronized(queue) {
            thread.newTasksMayBeScheduled = false;
            queue.clear();
            queue.notify();  // In case queue was already empty.
        }
    }
    private void sched(TimerTask task, long time, long period) {
        if (time < 0)
            throw new IllegalArgumentException("Illegal execution time.");
        // Constrain value of period sufficiently to prevent numeric
        // overflow while still being effectively infinitely large.
        if (Math.abs(period) > (Long.MAX_VALUE >> 1))
            period >>= 1;
        synchronized(queue) {
            if (!thread.newTasksMayBeScheduled)　　　　　　　　　　　　　　　　　　//調(diào)度器已經(jīng)停止則拋出異常
                throw new IllegalStateException("Timer already cancelled.");
            synchronized(task.lock) {
                if (task.state != TimerTask.VIRGIN)
                    throw new IllegalStateException(
                        "Task already scheduled or cancelled");
                task.nextExecutionTime = time;
                task.period = period;
                task.state = TimerTask.SCHEDULED;
            }
            queue.add(task);
            if (queue.getMin() == task)
                queue.notify();
        }
    }