JavaThread等待/通知经典范式

JavaThread等待/通知经典范式

package com.stono.thread;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.concurrent.TimeUnit;

public class WaitNotify {
    static boolean flag = true;
    static Object lock = new Object();
    
    public static void main(String[] args) throws InterruptedException {
        Thread waitThread = new Thread(new Wait(), "WaitThread");
        waitThread.start();
        TimeUnit.SECONDS.sleep(10);
        Thread notifyThread = new Thread(new Notify(), "NotifyThread");
        notifyThread.start();
    }
    
    static class Wait implements Runnable{

        @Override
        public void run() {
            // 加锁，拥有lock的Monitor
            synchronized (lock) {
                // 当条件满足时，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 (Exception e) {
                        e.printStackTrace();
                    }
                }
                // 条件不满足时，完成工作
                System.out.println(Thread.currentThread()+" flag is false. running @"+new SimpleDateFormat("HH:mm:ss").format(new Date()));
            }
        }
        
    }
    static class Notify implements Runnable{

        @Override
        public void run() {
            // 加锁，拥有lock的Monitor
            synchronized (lock) {
                // 获取lock的锁，然后进行通知，通知时不会释放lock的锁，
                // 直到当前线程释放了lock后，WaitThread才能从wait方法中返回
                System.out.println(Thread.currentThread() + " hold lock. notify @ "+ new SimpleDateFormat("HH:mm:ss").format(new Date()));
                lock.notifyAll();
                flag = false;
                SleepUtils.second(10);
            }
            // 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(10);
            }
        }
        
    }
}

经典范式

synchronized(object){

　　while(条件不满足){

　　　　object.wait();

　　}

　　逻辑处理；

}

synchronized(object){

　　改变条件

　　object.notifyAll();

}