Timer延时执行与ScheduledExecutorService的区别

最新推荐文章于 2025-03-13 19:09:32 发布

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最新推荐文章于 2025-03-13 19:09:32 发布

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分类专栏： java 文章标签： java

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本文探讨了在Java中使用Timer和ScheduledExecutorService进行延时执行时的区别。当Timer任务抛出异常时，整个线程会终止，无法继续执行后续任务，而ScheduledExecutorService遇到异常则不会影响其他任务的执行，展示了两者在错误处理上的不同策略。

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在执行延时执行的时候，Timer抛出异常之后会出现线程终止，无法进行下个线程的执行（利用idea中的插件检测出来的）

上代码

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

public class TimerTest {
    private Timer timer = new Timer();

    public void launchTimer() {
        timer.schedule(new TimerTask(){
            @Override
            public void run() {
                System.out.println("launchTimer");
                throw new RuntimeException();
            }
        }, 1000*3, 500);
    }

    public void addOneTask() {
        timer.schedule(new TimerTask(){
            @Override
            public void run() {
                System.out.println("hello world");
            }
        }, 1000*1, 1000*5);
    }

    public static void main(String[] args) throws InterruptedException {
        TimerTest test = new TimerTest();
        test.launchTimer();
        Thread.sleep(5000);
        test.addOneTask();
    }
}

Timer执行延迟的时候会出现第一个 launchTimer出现异常，整个任务就会终止，addOneTask不会继续执行

会出现这种报错（执行第一个之后，运行终止） Timer运行结果

但是将Timer更换成ScheduledExecutorService之后，代码如下

import org.apache.commons.lang3.concurrent.BasicThreadFactory;

import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class TestScheduledExecutorService {
    private ScheduledExecutorService executorService = new ScheduledThreadPoolExecutor(1,
            new BasicThreadFactory.Builder().namingPattern("example-schedule-pool-%d").build());


    public void launchTimer() {
        executorService.scheduleAtFixedRate(new Runnable() {
            @Override
            public void run() {
                System.out.println("launchTimer");
                try {
                    throw new Exception();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        },1000*3, 500, TimeUnit.MILLISECONDS);
    }

    public void addOneTask() {
        executorService.scheduleAtFixedRate(new Runnable() {
            @Override
            public void run() {
                System.out.println("addOneTask");
            }
        },500,1000*5,TimeUnit.MILLISECONDS);
    }

    public static void main(String[] args) throws InterruptedException {
        TestScheduledExecutorService testScheduledExecutorService = new TestScheduledExecutorService();
        testScheduledExecutorService.launchTimer();
        Thread.sleep(5000);
        testScheduledExecutorService.addOneTask();
    }
}

执行结果如下 ScheduledExecutorService运行结果

launchTimer
java.lang.Exception
	at com.medical.design.controller.website.TestScheduledExecutorService$1.run(TestScheduledExecutorService.java:22)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
java.lang.Exception
	at com.medical.design.controller.website.TestScheduledExecutorService$1.run(TestScheduledExecutorService.java:22)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
launchTimer
launchTimer
java.lang.Exception
	at com.medical.design.controller.website.TestScheduledExecutorService$1.run(TestScheduledExecutorService.java:22)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
launchTimer
java.lang.Exception
	at com.medical.design.controller.website.TestScheduledExecutorService$1.run(TestScheduledExecutorService.java:22)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
launchTimer
java.lang.Exception
	at com.medical.design.controller.website.TestScheduledExecutorService$1.run(TestScheduledExecutorService.java:22)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
launchTimer
java.lang.Exception
	at com.medical.design.controller.website.TestScheduledExecutorService$1.run(TestScheduledExecutorService.java:22)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
addOneTask
launchTimer
java.lang.Exception
	at com.medical.design.controller.website.TestScheduledExecutorService$1.run(TestScheduledExecutorService.java:22)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
java.lang.Exception
	at com.medical.design.controller.website.TestScheduledExecutorService$1.run(TestScheduledExecutorService.java:22)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
launchTimer
...........

ScheduledExecutorService运行的时候遇到异常不会影响下一个线程的执行，而Timer遇到异常之后会出现直接终止

或者将ScheduledExecutorService其中的 throw new Exception();更改为 throw new RuntimeException();

import org.apache.commons.lang3.concurrent.BasicThreadFactory;

import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class TestScheduledExecutorService {
    private ScheduledExecutorService executorService = new ScheduledThreadPoolExecutor(1,
            new BasicThreadFactory.Builder().namingPattern("example-schedule-pool-%d").build());


    public void launchTimer() {
        executorService.scheduleAtFixedRate(new Runnable() {
            @Override
            public void run() {
                System.out.println("launchTimer");
                throw new RuntimeException();
            }
        },1000*3, 500, TimeUnit.MILLISECONDS);
    }

    public void addOneTask() {
        executorService.scheduleAtFixedRate(new Runnable() {
            @Override
            public void run() {
                System.out.println("addOneTask");
            }
        },500,1000*5,TimeUnit.MILLISECONDS);
    }

    public static void main(String[] args) throws InterruptedException {
        TestScheduledExecutorService testScheduledExecutorService = new TestScheduledExecutorService();
        testScheduledExecutorService.launchTimer();
        Thread.sleep(5000);
        testScheduledExecutorService.addOneTask();
    }
}

执行结果是

launchTimer
addOneTask
addOneTask
addOneTask
addOneTask
.........