JUC学习之读写锁-蒲公英云

JUC学习之读写锁

Dear 丶 2022-05-19 08:44 259阅读 0赞

读写锁：（并发情况下比独占锁效率要高，适用于读操作频率高，写频率低的场景）
- 写写、读写（互斥）
- 读读（不互斥）

public class Test { 
    public static void main(String[] args) {
        ReadWriteLockDemo demo = new ReadWriteLockDemo();
        // 单个线程去写
        new Thread(() -> demo.setNumber(new Random().nextInt()), "Write：").start();
        // 多个线程并发的去读
        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() {
        // 加读锁
        lock.readLock().lock();
        try {
            System.out.println(Thread.currentThread().getName() + " : " + number);
        } finally {
            // 释放读锁
            lock.readLock().unlock();
        }
    }
    public void setNumber(int number) {
        // 加写锁
        lock.writeLock().lock();
        try {
            System.out.println(Thread.currentThread().getName() + " : " + number);
            this.number = number;
        } finally {
            // 释放写锁
            lock.writeLock().unlock();
        }
    }
}