详解SpringBoot定时任务功能

  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。

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;
  
  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
          }
      }
  }
  
  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<Runnable, ScheduledTask> 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<Runnable> 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 {
   
   @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;
}

public void executeTask(Long taskId) {
    if (!redisService.setIfAbsent(String.valueOf(taskId),"1",2L, TimeUnit.SECONDS)) {
        log.info("已有执行中定时发送短信任务，本次不执行！");
        return;
    }