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

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);
}
}

运行的结果如下：立刻执行，而且每隔100毫秒执行一次。

run 1501051231331
run 1501051231427
run 1501051231527
run 1501051231628
run 1501051231726
run 1501051231827
run 1501051231926
run 1501051232026
run 1501051232127
.......

二、ScheduledExecutorService使用Callable延迟运行

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";
}
}
}

运行的结果如下：

三、使用scheduleWithFixedDelay()方法实现周期性执行

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();
}
}
}
}

运行的结果如下：

友情链接

可以参考博客：http://blog.csdn.net/cages/article/details/7300992

关于spring中的定时器：http://blog.csdn.net/tsyj810883979/article/details/8481621