Java Review - 使用Timer时需要注意的事情

import java.util.Timer;
import java.util.TimerTask;

/**
 * @author 小工匠
 * @version 1.0
 * @description: TODO
 * @date 2021/11/21 20:28
 * @mark: show me the code , change the world
 */
public class TimerTest {

    // 定时器
    static Timer timer = new Timer();

    public static void main(String[] args) {

        // 任务1 , 延迟500ms执行  1秒执行一次
        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                System.out.println("Task1 Running");
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

                // 模拟发生异常
                throw new RuntimeException();
            }
        },500,1000);

        // 任务2, 延迟1000ms执行  1秒执行一次
        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                System.out.println("Task2 Running");
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        },1000,1000);
    }
}

/**
 * This "helper class" implements the timer's task execution thread, which
 * waits for tasks on the timer queue, executions them when they fire,
 * reschedules repeating tasks, and removes cancelled tasks and spent
 * non-repeating tasks from the queue.
 */
class TimerThread extends Thread {
    /**
     * This flag is set to false by the reaper to inform us that there
     * are no more live references to our Timer object.  Once this flag
     * is true and there are no more tasks in our queue, there is no
     * work left for us to do, so we terminate gracefully.  Note that
     * this field is protected by queue's monitor!
     */
    boolean newTasksMayBeScheduled = true;

    /**
     * Our Timer's queue.  We store this reference in preference to
     * a reference to the Timer so the reference graph remains acyclic.
     * Otherwise, the Timer would never be garbage-collected and this
     * thread would never go away.
     */
    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();  // Eliminate obsolete references
            }
        }
    }

    /**
     * The main timer loop.  (See class comment.)
     */
    private void mainLoop() {
        while (true) {
            try {
                TimerTask task;
                boolean taskFired;
                // 从队列里面获取任务时要加锁
                synchronized(queue) {
                .........
                
                if (taskFired)  // Task fired; run it, holding no locks
                    task.run();// 执行任务
            } catch(InterruptedException e) {
            }
        }
    }
}

public class TimerTest {

 
    public static void main(String[] args) throws InterruptedException {
 

        ScheduledThreadPoolExecutor scheduledThreadPoolExecutor = new ScheduledThreadPoolExecutor(1);

        scheduledThreadPoolExecutor.schedule(()->{
            System.out.println("Task1 Running");
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            // 模拟发生异常
            throw new RuntimeException();
        },1, TimeUnit.SECONDS);


        scheduledThreadPoolExecutor.schedule(()->{
            System.out.println("Task2 Running");
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            // 关闭线程池
            scheduledThreadPoolExecutor.shutdown();

        },1, TimeUnit.SECONDS);
        
    }
    
}