Java多线程之《等待/通知机制》

synchronized(对象) { 
        while(条件不满足) { 
            对象.wait(); 
        } 
        完成任务逻辑 
     }

import java.text.SimpleDateFormat;import java.util.Date;/**
 * 线程等待/通知机制
 * Created by peng on 2018/7/22.
 */public class WaitNotify {

    private static boolean flag = true;    private static Object lock = new Object();    public static void main(String[] args) {
        Thread waitThread = new Thread(new Wait(), "WaitThread");
        waitThread.start();
        SleepUtils.second(1);

        Thread notifyThread = new Thread(new Notify(), "NotifyThread");
        notifyThread.start();
    }    private static class Wait implements Runnable {
        @Override
        public void run() {            // 加锁，拥有lock的Monitor
            synchronized (lock) {                // 当条件不满足时，继续wait，同时释放了lock的锁
                while (flag) {                    
                try {
                        System.out.println(Thread.currentThread() + " flag is true. wait @ "
                                + new SimpleDateFormat("HH:mm:ss").format(new Date()));
                        lock.wait();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }                // 条件满足时，完成工作
                System.out.println(Thread.currentThread() + " flag is false. running @ "
                        + new SimpleDateFormat("HH:mm:ss").format(new Date()));
            }
        }
    }    
    private static class Notify implements Runnable {
        @Override
        public void run() {            // 加锁，拥有lock的Monitor
            synchronized (lock) {
                System.out.println(Thread.currentThread() + " hold lock. notify @ "
                        + new SimpleDateFormat("HH:mm:ss").format(new Date()));
                lock.notifyAll();
                flag = false;
                SleepUtils.second(5);
            }            // 再次加锁
            synchronized (lock) {
                System.out.println(Thread.currentThread() + " hold lock again. sleep @ "
                        + new SimpleDateFormat("HH:mm:ss").format(new Date()));
                SleepUtils.second(5);
            }
        }
    }
}