ScheduledThreadPoolExecutor 继承自ThreadPoolExecutor实现了ScheduledExecutorService接口。主要完成定时或者周期的执行线程任务。
111.png
执行过程：
22.png
demo：
package thread;
import java.text.SimpleDateFormat;
import java.util.Date;
/**
* Created by Torres on 17/3/16.
*/
public class MyThread implements Runnable {
private String name;
public MyThread(String name) {
this.name = name;
}
public String getName() {
return name;
}
@Override
public void run() {
System.out.println(getName() + "true start:" + nowTime());
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(getName() + "true end:" + nowTime());
}
public static String nowTime() {
SimpleDateFormat dataFormate = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
return dataFormate.format(new Date());
}
}
package thread;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import org.testng.annotations.Test;
/**
* Created by Torres on 17/3/16.
*/
public class ScheduledThreadPoolTest {
@Test
public void testScheduleThread() {
ScheduledExecutorService scheduledExecutorService = Executors.newScheduledThreadPool(10);
System.out.println("main开始时间" + MyThread.nowTime());
for (int i = 0; i < 3; i++) {
MyThread myThread = new MyThread("thread" + i);
System.out.println("thread" + i + "开始时间" + MyThread.nowTime());
scheduledExecutorService.schedule(myThread, 5, TimeUnit.SECONDS);//延时5s 执行
//scheduledExecutorService.scheduleWithFixedDelay(myThread, 5, 2, TimeUnit.SECONDS);
}
try {
Thread.sleep(70000);
} catch (InterruptedException e) {
e.printStackTrace();
}
scheduledExecutorService.shutdown();//7s 后关闭不再接受执行线程
while (!scheduledExecutorService.isTerminated()) {//all thread等待结束
}
System.out.println("main结束时间" + MyThread.nowTime());
}
}
(1) scheduledExecutorService.schedule(myThread, 5, TimeUnit.SECONDS)
结果：
main开始时间2017-03-16 22:18:04
thread0开始时间2017-03-16 22:18:04
thread1开始时间2017-03-16 22:18:04
thread2开始时间2017-03-16 22:18:04
thread1true start:2017-03-16 22:18:09
thread0true start:2017-03-16 22:18:09
thread2true start:2017-03-16 22:18:09
thread1true end:2017-03-16 22:18:12
thread0true end:2017-03-16 22:18:12
thread2true end:2017-03-16 22:18:12
main结束时间2017-03-16 22:19:14
可以看出主线程启动子线程：scheduledExecutorService.schedule(myThread, 5, TimeUnit.SECONDS)后5S开始thread0,1,2开始执行。 scheduledExecutorService.shutdown();//7s 后关闭不再接受执行线程。shutdown()表示scheduledExecutorService关闭不再接受新的线程执行（如果线程已经开始，则等待此线程结束）这里如果没有 Thread.sleep(70000);则所有线程不会执行。while (!scheduledExecutorService.isTerminated()) {//all thread等待结束 这里是主线程等待所有的子线程结束
}
public ScheduledFuture<?> schedule(Runnable command,
long delay, TimeUnit unit);
启动线程后延时delay 个unit单位执行command 任务。只有一次
(2)scheduledExecutorService.scheduleWithFixedDelay(myThread, 5, 2, TimeUnit.SECONDS);
结果:
main开始时间2017-03-16 22:26:39
thread0开始时间2017-03-16 22:26:39
thread1开始时间2017-03-16 22:26:39
thread2开始时间2017-03-16 22:26:39
thread1true start:2017-03-16 22:26:44
thread0true start:2017-03-16 22:26:44
thread2true start:2017-03-16 22:26:44
thread1true end:2017-03-16 22:26:47
thread0true end:2017-03-16 22:26:47
thread2true end:2017-03-16 22:26:47
thread1true start:2017-03-16 22:26:49
thread0true start:2017-03-16 22:26:49
thread2true start:2017-03-16 22:26:49
thread2true end:2017-03-16 22:26:52
thread1true end:2017-03-16 22:26:52
thread0true end:2017-03-16 22:26:52
thread2true start:2017-03-16 22:26:54
thread1true start:2017-03-16 22:26:54
thread0true start:2017-03-16 22:26:54
thread0true end:2017-03-16 22:26:57
thread1true end:2017-03-16 22:26:57
thread2true end:2017-03-16 22:26:57
thread1true start:2017-03-16 22:26:59
thread2true start:2017-03-16 22:26:59
thread0true start:2017-03-16 22:26:59
可以看出线程开始延时5后首次执行，以后每隔2S周期执行任务。
public ScheduledFuture<?> scheduleWithFixedDelay(Runnable command,
long initialDelay,
long delay,
TimeUnit unit);
//初始的延迟initialDelay 结束后周期性地执行给定任务command，在一次调用完成和下一次调用开始之间有长度为delay的延迟。
