java高级---->Thread之ScheduledExecutorService的使用

java高级---->Thread之ScheduledExecutorService的使用

ScheduledExecutorService的主要作用就是可以将定时任务与线程池功能结合使用。今天我们来学习一下ScheduledExecutorService的用法。我们都太渺小了,那么容易便湮没于各自的殊途。 ScheduledExecutorService的简单使用 一、使用scheduleAtFixedRate()方法实现周期性执行 复制代码
public class ScheduledExecutorServiceTest { public static void main(String[] args) { ScheduledExecutorService executorService = Executors.newSingleThreadScheduledExecutor(); executorService.scheduleAtFixedRate(new Runnable() { @Override public void run() { System.out.println("run "+ System.currentTimeMillis()); } }, 0, 100, TimeUnit.MILLISECONDS); } } 复制代码 运行的结果如下:立刻执行,而且每隔100毫秒执行一次。 复制代码 run 1501051231331 run 1501051231427 run 1501051231527 run 1501051231628 run 1501051231726 run 1501051231827 run 1501051231926 run 1501051232026 run 1501051232127 ....... 复制代码 二、ScheduledExecutorService使用Callable延迟运行 复制代码 package com.linux.thread; import java.util.ArrayList; import java.util.List; import java.util.concurrent.*; public class CallableRun { public static void main(String[] args) { try { List<Callable> callableList = new ArrayList<>(); callableList.add(new MyCallableA()); callableList.add(new MyCallableB()); ScheduledExecutorService executorService = Executors.newSingleThreadScheduledExecutor(); ScheduledFuture futureA = executorService.schedule(callableList.get(0), 4L, TimeUnit.SECONDS); ScheduledFuture futureB = executorService.schedule(callableList.get(1), 4L, TimeUnit.SECONDS); System.out.println(" X = " + System.currentTimeMillis()); System.out.println("返回值A:" + futureA.get()); System.out.println("返回值B:" + futureB.get()); System.out.println(" Y = " + System.currentTimeMillis()); executorService.shutdown(); } catch (InterruptedException e) { e.printStackTrace(); } catch (ExecutionException e) { e.printStackTrace(); } } static class MyCallableA implements Callable<String> { @Override public String call() throws Exception{ try { System.out.println("callA begin " + Thread.currentThread().getName() + ", " + System.currentTimeMillis()); TimeUnit.SECONDS.sleep(3); // 休眠3秒 System.out.println("callA end " + Thread.currentThread().getName() + ", " + System.currentTimeMillis()); } catch (Exception e) { e.printStackTrace(); } return "returnA"; } } static class MyCallableB implements Callable<String> { @Override public String call() throws Exception{ System.out.println("callB begin " + Thread.currentThread().getName() + ", " + System.currentTimeMillis()); System.out.println("callB end " + Thread.currentThread().getName() + ", " + System.currentTimeMillis()); return "returnB"; } } } 复制代码 运行的结果如下: 三、使用scheduleWithFixedDelay()方法实现周期性执行 复制代码 package com.linux.thread; import java.util.concurrent.Executors; import java.util.concurrent.ScheduledExecutorService; import java.util.concurrent.TimeUnit; public class RunMain { public static void main(String[] args) { ScheduledExecutorService executorService = Executors.newSingleThreadScheduledExecutor(); System.out.println(" x = " + System.currentTimeMillis()); executorService.scheduleWithFixedDelay(new MyRunable(), 1, 2, TimeUnit.SECONDS); System.out.println(" y = " + System.currentTimeMillis()); } static class MyRunable implements Runnable { @Override public void run() { try { System.out.println(" begin = " + System.currentTimeMillis() + ", name: " + Thread.currentThread().getName()); TimeUnit.SECONDS.sleep(4); System.out.println(" end = " + System.currentTimeMillis() + ", name: " + Thread.currentThread().getName()); } catch (InterruptedException e) { e.printStackTrace(); } } } } 复制代码 运行的结果如下:

 

    原文作者:风轮
    原文地址: https://www.cnblogs.com/xiaolei2017/p/9548324.html
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