ReentrantReadWriteLock的使用

ReentrantReadWriteLock是AQS的一种实现，分为读锁（共享锁）和写锁（排他锁，独占锁），他可以做到在只有读的时候不阻塞，有写的时候阻塞，具体使用如下：

package test.lock.read.write.lock;

import java.util.concurrent.locks.ReentrantReadWriteLock;

/**
 * @author: xby
 * @Date: 2020/5/22 13:36
 */
public class TestReadWriteLock {

    private ReentrantReadWriteLock readWriteLock = new ReentrantReadWriteLock();
    private ReentrantReadWriteLock.ReadLock readLock = readWriteLock.readLock();
    private ReentrantReadWriteLock.WriteLock writeLock = readWriteLock.writeLock();

    public void readLock() {
        try {
            readLock.lock();
            System.out.println(Thread.currentThread().getName() + " read start ");
            Thread.sleep(1000);
            System.out.println(Thread.currentThread().getName() + " read end ");
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            readLock.unlock();
        }
    }

    public void writeLock() {

        try {
            writeLock.lock();
            System.out.println(Thread.currentThread().getName() + " write start ");
            Thread.sleep(1000);
            System.out.println(Thread.currentThread().getName() + " write end ");
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            writeLock.unlock();
        }
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

    }

    public static void main(String[] args) {
        TestReadWriteLock readWriteLock = new TestReadWriteLock();
//        Thread thread1 = new Thread(()->{readWriteLock.readLock();});
//        Thread thread2 = new Thread(()->{readWriteLock.readLock();});
        Thread thread1 = new Thread(()->{readWriteLock.readLock();});
        Thread thread2 = new Thread(()->{readWriteLock.writeLock();});
        thread1.start();
        thread2.start();
    }
}

根据测试如下：

都是读的时候不阻塞，有写的时候，读写都阻塞。