package BackStage;import java.util.concurrent.Executors;import java.util.concurrent.ExecutorService;public class JavaThreadPool {public static void main(String[] args) {// 创建一个可重用固定线程数的线程池ExecutorService pool = Executors.newFixedThreadPool(2);// 创建实现了Runnable接口对象，Thread对象当然也实现了Runnable接口Thread t1 = new MyThread();Thread t2 = new MyThread();Thread t3 = new MyThread();Thread t4 = new MyThread();Thread t5 = new MyThread();// 将线程放入池中进行执行
        pool.execute(t1);pool.execute(t2);pool.execute(t3);pool.execute(t4);pool.execute(t5);// 关闭线程池
        pool.shutdown();}
}class MyThread extends Thread {@Overridepublic void run() {System.out.println(Thread.currentThread().getName() + "正在执行。。。");}
}

class MyThread extends Thread {boolean stopped;MyThread(ThreadGroup tg, String name) {super(tg, name);stopped = false;}public void run() {System.out.println(Thread.currentThread().getName() + " starting.");try {for (int i = 1; i < 1000; i++) {System.out.print(".");Thread.sleep(250);synchronized (this) {if (stopped)break;}}} catch (Exception exc) {System.out.println(Thread.currentThread().getName() + " interrupted.");}System.out.println(Thread.currentThread().getName() + " exiting.");}synchronized void myStop() {stopped = true;}
}public class Main {public static void main(String args[]) throws Exception {ThreadGroup tg = new ThreadGroup("My Group");MyThread thrd = new MyThread(tg, "MyThread #1");MyThread thrd2 = new MyThread(tg, "MyThread #2");MyThread thrd3 = new MyThread(tg, "MyThread #3");thrd.start();thrd2.start();thrd3.start();Thread.sleep(1000);System.out.println(tg.activeCount() + " threads in thread group.");Thread thrds[] = new Thread[tg.activeCount()];tg.enumerate(thrds);for (Thread t : thrds)System.out.println(t.getName());thrd.myStop();Thread.sleep(1000);System.out.println(tg.activeCount() + " threads in tg.");tg.interrupt();}
}