Java多線程與併發_Synchronized和Lock實現生產者消費者模式

Java多線程與併發_Synchronized和Lock實現生產者消費者模式

能自己扛，就別聲張​

一、生產者消費者例子

現在兩個線程
可以操作初始值爲零的一個變量，
實現一個線程對該變量加1，一個線程對該變量減1
交替，來10輪，變量初始值爲零

二、Synchronized實現

/**
 * @Author: slx
 * @Date: 2019/4/24 19:09
 */
public class NotifyWaitDemoReview {
    public static void main(String[] args) {
        //線程操縱資源類
        ShareData shareData = new ShareData();

        //生產者
        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try {
                    shareData.increment();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        },"AA").start();

        //消費者
        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try {
                    shareData.decrement();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        },"BB").start();
    }
}

class ShareData {
    private int number = 0;


    public synchronized void increment() throws InterruptedException {
        //1.判斷
        while (number != 0) {
            this.wait();
        }

        //2.幹活
        ++number;
        System.out.println(Thread.currentThread().getName() + "\t" + number);

        //3.通知
        this.notifyAll();
    }

    public synchronized void decrement() throws InterruptedException {
        //1.判斷
        while (number == 0) {
            this.wait();
        }
        //2.幹活
        --number;
        System.out.println(Thread.currentThread().getName() + "\t" + number);
        //3.通知
        this.notifyAll();
    }
}

三、Lock實現

class ShareData {
    private int number = 0;

    private Lock lock = new ReentrantLock();
    private Condition condition = lock.newCondition();

    public void increment() throws InterruptedException {
        lock.lock();

        try {
            //1.判斷
            while (number != 0) {
//                this.wait();
                condition.await();
            }
            //2.幹活
            ++number;
            System.out.println(Thread.currentThread().getName() + "\t" + number);
            //3.通知
//            this.notifyAll();
            condition.signalAll();
        }catch (InterruptedException e) {
            e.printStackTrace();
        }finally {
            lock.unlock();
        }
    }

    public void decrement() throws InterruptedException {
        lock.lock();
        try {
            //1.判斷
            while (number == 0) {
//                this.wait();
                condition.await();
            }
            //2.幹活
            --number;
            System.out.println(Thread.currentThread().getName() + "\t" + number);
            //3.通知
//            this.notifyAll();
            condition.signalAll();
        }catch (InterruptedException e) {
            e.printStackTrace();
        }finally {
            lock.unlock();
        }
    }
}

四、結果

AA	1
BB	0
AA	1
BB	0
AA	1
BB	0
AA	1
BB	0
AA	1
BB	0
AA	1
BB	0
AA	1
BB	0
AA	1
BB	0
AA	1
BB	0
AA	1
BB	0

Process finished with exit code 0