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  • lock、tryLock和lockInterruptibly的差別

    lock():若lock被thread A取得,thread B会进入block状态,直到取得lock;
    tryLock():若当下不能取得lock,thread就会放弃,可以设置一个超时时间参数,等待多久获取不到锁就放弃;
    lockInterruptibly():跟lock()情況一下,但是thread B可以通过interrupt中断,放弃继续等待锁

    lock 与 lockInterruptibly比较区别在于:lock 优先考虑获取锁,待获取锁成功后,才响应中断,而lockInterruptibly 优先考虑响应中断 

    ReentrantLock.lockInterruptibly允许在等待时由其它线程调用等待线程的Thread.interrupt方法来中断等待线程的等待而直接返回,这时不用获取锁,而会抛出一个InterruptedException

    ReentrantLock.lock方法不允许Thread.interrupt中断,即使检测到Thread.isInterrupted,一样会继续尝试获取锁,失败则继续休眠。只是在最后获取锁成功后再把当前线程置为interrupted状态,然后再中断线程

    public class LockDemo {
    
        private ReentrantLock lock = new ReentrantLock();
    
        public static void main(String[] args) throws InterruptedException {
            final LockDemo lockDemo = new LockDemo();
    
            Thread threada = new Thread("Thread A") {
                @Override
                public void run() {
                    lockDemo.doSomeThing3(Thread.currentThread());
                }
            };
            threada.start();
    
            Thread threadb = new Thread("Thread B") {
                @Override
                public void run() {
                    lockDemo.doSomeThing3(Thread.currentThread());
                }
            };
            threadb.start();
            
            //threadb.interrupt();
        }
    
        public void doSomeThing1(Thread thread) {
            lock.lock();
            try {
                System.out.println(thread.getName() + "得到了锁.");
                Thread.sleep(1000);
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                System.out.println(thread.getName() + "释放了锁.");
                lock.unlock();
            }
        }
        
        
        public void doSomeThing2(Thread thread) {
            if (lock.tryLock()) {
                try {
                    System.out.println(thread.getName() + "得到了锁.");
                    Thread.sleep(1000);
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    System.out.println(thread.getName() + "释放了锁.");
                    lock.unlock();
                }
            } else {
                System.out.println(thread.getName() + "获取锁失败.");
            }
        }
    
        public void doSomeThing3(Thread thread) {
            try {
                lock.lockInterruptibly();
                System.out.println(thread.getName() + " 得到了锁.");
                Thread.sleep(6000);
            } catch (InterruptedException e1) {
                e1.printStackTrace();
                System.out.println(thread.getName() + " interrupted.");
            } finally {
                System.out.println(thread.getName() + " 释放了锁.");
                lock.unlock();
            }
        }
    
    }

     

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  • 原文地址:https://www.cnblogs.com/moris5013/p/11726502.html
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