QA

超、凢脫俗 2022-06-11 01:54 205阅读 0赞

疑问： 为什么t1.open() 调用notifyAll()的时候，t2, t3为什么不释放？还在wait等待状态

import java.util.concurrent.ExecutorService;
    import java.util.concurrent.Executors;
    
    /** * Created by arthur.dy.lee on 2017/6/29. */
    //public class Test implements Runnable { 
    public class MyThread extends Thread { 
    
        public boolean isOpen;
        private Integer generation = 1;
    
        public synchronized void open() {
            ++generation;
            isOpen = true;
            notifyAll();
        }
    
        public synchronized void close() {
            isOpen = false;
        }
    
        public synchronized void wait1() {
            while (!isOpen) {
                System.out.println(currentThread().getName() + ", in while");
                try {
                    wait();
    
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            System.out.println(currentThread().getName() + ", out while");
        }
    
        public synchronized void wait2() {
            int arrivalGeneration = generation;
            while (!isOpen && arrivalGeneration == generation) {
                System.out.println(currentThread().getName() + ", in while");
                try {
                    wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            System.out.println(currentThread().getName() + ", out while");
        }
    
        public void run() {
    // wait2();
            wait1();
            System.out.println(currentThread().getName());
        }
    
        public boolean isOpen() {
            return isOpen;
        }
    
        public void setOpen(boolean open) {
            isOpen = open;
        }
    
        public static void main(String[] args) throws InterruptedException {
            Object obj;
            ExecutorService pool = Executors.newFixedThreadPool(5);
            // 创建线程
            MyThread t1 = new MyThread();
            MyThread t2 = new MyThread();
            MyThread t3 = new MyThread();
    
            // 将线程放入池中进行执行
            pool.execute(t1);
            pool.execute(t2);
            pool.execute(t3);
    
            long t0 = System.currentTimeMillis();
            for (; ; ) {
                if ((System.currentTimeMillis() - t0) > 100) {
                    break;
                }
            }
    
            t1.open();
    
    
            /* t1.join(); synchronized (MyThread.class) { System.out.println("get lock, "+currentThread().getName()); t3.notifyAll(); }*/
            //t2.open();
    
            //t1.close();
            //t3.open();
    
    
    
            // t3.open();
            //TimeUnit.SECONDS.sleep(2);
            // System.out.println("t2.close");
    // t2.close();
    // t3.close();
    
            // 关闭线程池
            pool.shutdown();
    
        }
    }