线程间的通信

package juc;

import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

/**
 * 题目：现在两个线程，可以操作初始值为零的一个变量
 * 实现一个线程对该变量加一，一个线程对该变量减一
 * 实现交替，来10轮，变量初始值为0
 */
public class ThreadWaitNotifyDemo {
    public static void main(String[] args) {
        AirConditioner airConditioner = new AirConditioner();
        new Thread(() -> { for (int i = 0; i < 10; i++) {
            try {
                airConditioner.increase();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        }, "A").start();
        new Thread(() -> { for (int i = 0; i < 10; i++) {
            try {
                airConditioner.decrease();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        }, "B").start();
    }
}
// 资源类
class AirConditioner {
    private int num = 0;
    Lock lock = new ReentrantLock();

    public synchronized void increase() throws InterruptedException {
            // 1.判断
            if(num != 0){
                this.wait();
            }
            // 2.干活
            System.out.println(num+"被"+Thread.currentThread().getName()+"进行加一后为:"+ ++num);
            // 3.通知
            this.notify();
    }
    public synchronized void decrease() throws InterruptedException {
            // 1.判断
            if(num == 0){
                this.wait();
            }
            // 2.干活
            System.out.println(num+"被"+Thread.currentThread().getName()+"进行减一后为:"+ --num);
            // 3.通知
            this.notify();
    }
}

package juc;

import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

/**
 * 题目：现在两个线程，可以操作初始值为零的一个变量
 * 实现一个线程对该变量加一，一个线程对该变量减一
 * 实现交替，来10轮，变量初始值为0
 * <p>
 * 1.在高内聚低耦合的前提下，  线程  操作(对外暴露的调用方法)  资源类
 * 2.判断/干活/通知
 */
public class ThreadWaitNotifyDemo {
    public static void main(String[] args) {
        AirConditioner airConditioner = new AirConditioner();
        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try {
                    airConditioner.increase();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "A").start();
        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try {
                    airConditioner.increase();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "B").start();
        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try {
                    airConditioner.decrease();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "C").start();
        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try {
                    airConditioner.decrease();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "D").start();
    }
}

// 资源类
class AirConditioner {
    private int num = 0;
    Lock lock = new ReentrantLock();

    public synchronized void increase() throws InterruptedException {
        // 1.判断
        if (num != 0) {
            this.wait();
        }
        // 2.干活
        System.out.println(num + "被" + Thread.currentThread().getName() + "进行加一后为:" + ++num);
        // 3.通知
        this.notify();
    }

    public synchronized void decrease() throws InterruptedException {
        // 1.判断
        if (num == 0) {
            this.wait();
        }
        // 2.干活
        System.out.println(num + "被" + Thread.currentThread().getName() + "进行减一后为:" + --num);
        // 3.通知
        this.notify();
    }
}

package juc;

import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

/**
 * 题目：现在两个线程，可以操作初始值为零的一个变量
 * 实现一个线程对该变量加一，一个线程对该变量减一
 * 实现交替，来10轮，变量初始值为0
 * <p>
 * 1.在高内聚低耦合的前提下，  线程  操作(对外暴露的调用方法)  资源类
 * 2.判断/干活/通知
 * 3.多线程交互中，必须防止多线的虚假唤醒 (也即判断只能用while，不能用if)
 */
public class ThreadWaitNotifyDemo {
    public static void main(String[] args) {
        AirConditioner airConditioner = new AirConditioner();
        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try {
                    airConditioner.increase();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "A").start();
        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try {
                    airConditioner.increase();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "B").start();
        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try {
                    airConditioner.decrease();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "C").start();
        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try {
                    airConditioner.decrease();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "D").start();
    }
}

// 资源类
class AirConditioner {
    private int num = 0;
    Lock lock = new ReentrantLock();

    public synchronized void increase() throws InterruptedException {
        // 1.判断
        while (num != 0) {
            this.wait();
        }
        // 2.干活
        System.out.println(num + "被" + Thread.currentThread().getName() + "进行加一后为:" + ++num);
        // 3.通知
        this.notify();
    }

    public synchronized void decrease() throws InterruptedException {
        // 1.判断
        while (num == 0) {
            this.wait();
        }
        // 2.干活
        System.out.println(num + "被" + Thread.currentThread().getName() + "进行减一后为:" + --num);
        // 3.通知
        this.notify();
    }
}