Java多线程之ReentrantReadWriteLock基础篇

ReentrantReadWriteLock简介

• 分为读锁和写锁，读锁是共享锁（仅仅对需获取读锁的线程共享，如线程需要获取写锁则阻塞），写锁是排他锁，示例代码如下

  public class MyReadWriteLock {
      private static ReentrantReadWriteLock reentrantReadWriteLock = new ReentrantReadWriteLock();
      public static void main(String[] args) {
          ReentrantReadWriteLock.ReadLock readLock = reentrantReadWriteLock.readLock();
          ReentrantReadWriteLock.WriteLock writeLock = reentrantReadWriteLock.writeLock();
          /*
          * 1、Thread-1加写锁，Thread-2阻塞
          * 2、Thread-1加读锁，Thread-2需要获取读锁则Thread-2阻塞反之则能获取到锁
          * 3、以上很好的证明了读锁属于共享锁，而写锁属于排它锁
          * */
          new Thread(()->{
              method(writeLock);
          },"Thread-1").start();
          new Thread(()->{
              method(readLock);
          },"Thread-2").start();
      }
      private static void method(Lock lock){
          /*此处为了方便模拟读锁与写锁的共享性质和排他性质，
          *故意只加锁不释放锁
          * */
          lock.lock();
          System.out.println(Thread.currentThread().getName());
      }
  }