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等待和通知

Object对象提供了wait( ) 方法和 notify ( ) 方法。

wait( )方法需要配对着synchronized 关键字使用。

当一个线程的资源调用 wait( )方法时，它会失去锁，然后进入等待序列。

当其他线程调用notify方法时才会重新激活。

实例：

package com.xm.thread.t_19_01_27;

import java.util.concurrent.TimeUnit;

public class NotifyAndWait{

    private static Object object = new Object();


    static class WaitThread extends Thread{

        @Override
        public void run() {
            System.out.println("WaitThread Start!");
            try {
                System.out.println("Object wait!!!");
                synchronized (object) {
                    object.wait();
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("WaitThread Finish!");
        }
    }

    static class NotifyThread extends Thread{

        @Override
        public void run() {
            System.out.println("NotifyThread Start!");
            System.out.println("Object notify");
            synchronized (object) {
                object.notify();
            }
            System.out.println("NotifyThread Finish!");
        }
    }



    public static void main(String[] args) throws InterruptedException {
        new WaitThread().start();

        TimeUnit.SECONDS.sleep(5);

        new NotifyThread().start();

    }
}

运行结果：

WaitThread Start!

Object wait!!!

NotifyThread Start!

Object notify

NotifyThread Finish!

WaitThread Finish!

notify( )方法只会随机激活等待序列中的一个线程，而notifyAll( )方法激活所有等待的线程。

实例：

package com.xm.thread.t_19_01_27;

import java.util.concurrent.TimeUnit;

public class NotifyAndWait{

    private static Object object = new Object();


    static class WaitThread extends Thread{

        @Override
        public void run() {
            System.out.println("WaitThread Start!");
            try {
                System.out.println("Object wait!!!");
                synchronized (object) {
                    object.wait();
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("WaitThread Finish!");
        }
    }

    static class NotifyThread extends Thread{

        @Override
        public void run() {
            System.out.println("NotifyThread Start!");
            System.out.println("Object notify");
            synchronized (object) {
                object.notify();
            }
            System.out.println("NotifyThread Finish!");
        }
    }



    public static void main(String[] args) throws InterruptedException {
        new WaitThread().start();

        new WaitThread().start();

        TimeUnit.SECONDS.sleep(5);

        new NotifyThread().start();

    }
}

运行结果：

WaitThread Start!

Object wait!!!

WaitThread Start!

Object wait!!!

NotifyThread Start!

Object notify

NotifyThread Finish!

WaitThread Finish!

结果分析：

两个WaitThread线程只被唤醒了一个。

实例：

package com.xm.thread.t_19_01_27;

import java.util.concurrent.TimeUnit;

public class NotifyAndWait{

    private static Object object = new Object();


    static class WaitThread extends Thread{

        @Override
        public void run() {
            System.out.println("WaitThread Start!");
            try {
                System.out.println("Object wait!!!");
                synchronized (object) {
                    object.wait();
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("WaitThread Finish!");
        }
    }

    static class NotifyThread extends Thread{

        @Override
        public void run() {
            System.out.println("NotifyThread Start!");
            System.out.println("Object notify");
            synchronized (object) {
                object.notifyAll();
            }
            System.out.println("NotifyThread Finish!");
        }
    }



    public static void main(String[] args) throws InterruptedException {
        new WaitThread().start();

        new WaitThread().start();

        TimeUnit.SECONDS.sleep(5);

        new NotifyThread().start();

    }
}

运行结果：

WaitThread Start!

Object wait!!!

WaitThread Start!

Object wait!!!

NotifyThread Start!

Object notify

NotifyThread Finish!

WaitThread Finish!

WaitThread Finish!

结果分析：

notifyAll( )方法会唤醒处在等待序列中的所有线程。

4.等待和通知

标签：其他   对象   ace   port   over   cat   package   一个   interrupt   

原文地址：https://www.cnblogs.com/TimerHotel/p/thread04.html