SpringBoot 예약 작업 기능 구현 방법

public class MyTimerTask extends TimerTask { private String name; public MyTimerTask(String name){ this.name = name; } public String getName() { return name; } public void setName(String name) { this.name = name; } @Override public void run() { //task Calendar instance = Calendar.getInstance(); System.out.println(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(instance.getTime())); } } Timer timer = new Timer(); MyTimerTask timerTask = new MyTimerTask("NO.1"); //首次执行,在当前时间的1秒以后,之后每隔两秒钟执行一次 timer.schedule(timerTask,1000L,2000L);

//org.apache.commons.lang3.concurrent.BasicThreadFactory ScheduledExecutorService executorService = new ScheduledThreadPoolExecutor(1, new BasicThreadFactory.Builder().namingPattern("example-schedule-pool-%d").daemon(true).build()); executorService.scheduleAtFixedRate(new Runnable() { @Override public void run() { //do something } },initialDelay,period, TimeUnit.HOURS);

多线程并行处理定时任务时，Timer运行多个TimeTask时，只要其中之一没有捕获抛出的异常，其它任务便会自动终止运行，使用ScheduledExecutorService则没有这个问题。

/** * The timer thread. */ private final TimerThread thread = new TimerThread(queue); public Timer() { this("Timer-" + serialNumber()); } public Timer(String name) { thread.setName(name); thread.start(); }

class TimerThread extends Thread { boolean newTasksMayBeScheduled = true; /** * 每一件一个任务都是一个quene */ private TaskQueue queue; TimerThread(TaskQueue queue) { this.queue = queue; } public void run() { try { mainLoop(); } finally { // Someone killed this Thread, behave as if Timer cancelled synchronized(queue) { newTasksMayBeScheduled = false; queue.clear(); // 清除所有任务信息 } } } /** * The main timer loop. (See class comment.) */ 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) { } } } }

@Component public class CronTaskRegistrar implements DisposableBean { private final Map scheduledTasks = new ConcurrentHashMap<>(16); @Autowired private TaskScheduler taskScheduler; public TaskScheduler getScheduler() { return this.taskScheduler; } public void addCronTask(Runnable task, String cronExpression) { addCronTask(new CronTask(task, cronExpression)); } private void addCronTask(CronTask cronTask) { if (cronTask != null) { Runnable task = cronTask.getRunnable(); if (this.scheduledTasks.containsKey(task)) { removeCronTask(task); } this.scheduledTasks.put(task, scheduleCronTask(cronTask)); } } public void removeCronTask(Runnable task) { Set runnables = this.scheduledTasks.keySet(); Iterator it1 = runnables.iterator(); while (it1.hasNext()) { SchedulingRunnable schedulingRunnable = (SchedulingRunnable) it1.next(); Long taskId = schedulingRunnable.getTaskId(); SchedulingRunnable cancelRunnable = (SchedulingRunnable) task; if (taskId.equals(cancelRunnable.getTaskId())) { ScheduledTask scheduledTask = this.scheduledTasks.remove(schedulingRunnable); if (scheduledTask != null){ scheduledTask.cancel(); } } } } public ScheduledTask scheduleCronTask(CronTask cronTask) { ScheduledTask scheduledTask = new ScheduledTask(); scheduledTask.future = this.taskScheduler.schedule(cronTask.getRunnable(), cronTask.getTrigger()); return scheduledTask; } @Override public void destroy() throws Exception { for (ScheduledTask task : this.scheduledTasks.values()) { task.cancel(); } this.scheduledTasks.clear(); } }

public interface TaskScheduler { /** * Schedule the given {@link Runnable}, invoking it whenever the trigger * indicates a next execution time. * 
Execution will end once the scheduler shuts down or the returned * {@link ScheduledFuture} gets cancelled. * @param task the Runnable to execute whenever the trigger fires * @param trigger an implementation of the {@link Trigger} interface, * e.g. a {@link org.springframework.scheduling.support.CronTrigger} object * wrapping a cron expression * @return a {@link ScheduledFuture} representing pending completion of the task, * or {@code null} if the given Trigger object never fires (i.e. returns * {@code null} from {@link Trigger#nextExecutionTime}) * @throws org.springframework.core.task.TaskRejectedException if the given task was not accepted * for internal reasons (e.g. a pool overload handling policy or a pool shutdown in progress) * @see org.springframework.scheduling.support.CronTrigger */ @Nullable ScheduledFuture schedule(Runnable task, Trigger trigger);

@Configuration public class SchedulingConfig { @Bean public TaskScheduler taskScheduler() { ThreadPoolTaskScheduler taskScheduler = new ThreadPoolTaskScheduler(); // 定时任务执行线程池核心线程数 taskScheduler.setPoolSize(4); taskScheduler.setRemoveOnCancelPolicy(true); taskScheduler.setThreadNamePrefix("TaskSchedulerThreadPool-"); return taskScheduler; } }

public ScheduledExecutorService getScheduledExecutor() throws IllegalStateException { Assert.state(this.scheduledExecutor != null, "ThreadPoolTaskScheduler not initialized"); return this.scheduledExecutor; }