JUC學習之讀寫鎖

版權聲明：本文爲博主原創文章，未經博主允許不得轉載。 https://blog.csdn.net/qq_34560242/article/details/81169150

讀寫鎖：（併發情況下比獨佔鎖效率要高，適用於讀操作頻率高，寫頻率低的場景）
- 寫寫、讀寫（互斥）
- 讀讀（不互斥）

public class Test {

    public static void main(String[] args) {
        ReadWriteLockDemo demo = new ReadWriteLockDemo();

        // 單個線程去寫
        new Thread(() -> demo.setNumber(new Random().nextInt()), "Write：").start();

        // 多個線程併發的去讀
        for (int i = 0; i < 100; i++) {
            new Thread(() -> demo.getNumber(), "Read：").start();
        }
    }
}

class ReadWriteLockDemo {

    private int number = 0;

    private ReadWriteLock lock = new ReentrantReadWriteLock();

    public void getNumber() {
        // 加讀鎖
        lock.readLock().lock();
        try {
            System.out.println(Thread.currentThread().getName() + " : " + number);
        } finally {
            // 釋放讀鎖
            lock.readLock().unlock();
        }
    }

    public void setNumber(int number) {
        // 加寫鎖
        lock.writeLock().lock();
        try {
            System.out.println(Thread.currentThread().getName() + " : " + number);
            this.number = number;
        } finally {
            // 釋放寫鎖
            lock.writeLock().unlock();
        }
    }
}