public class ReentrantDemo {    //重入锁 保护临界区资源count，确保多线程对count操作的安全性    /*public static ReentrantLock rtlock = new ReentrantLock();    public static int count = 0;    Thread t = new Thread(new Runnable() {        @Override        public void run() {            for(int i=0;i<100000;i++){                rtlock.lock();                try{                    count++;                }finally {                    rtlock.unlock();                }            }        }    });*/    //重入锁 对于死锁的中断响应    public static ReentrantLock rtlock1 = new ReentrantLock();    public static ReentrantLock rtlock2 = new ReentrantLock();    private int lock;    public ReentrantDemo(int lock){        this.lock = lock;    }    Thread t = new Thread(new Runnable() {        @Override        public void run() {            try{                if(lock == 1){                    /*                    当两个线程同时通过lock.lockInterruptibly()想获取某个锁时，假若此时线程A获取到了锁，                    而线程B只有等待，那么对线程B调用threadB.interrupt()方法能够中断线程B的等待过程                    注意是：等待的那个线程B可以被中断，不是正在执行的A线程被中断                     */                    rtlock1.lockInterruptibly();                    try{                        Thread.sleep(3000);                    }catch (InterruptedException e){                    }                    rtlock2.lockInterruptibly();                }                else{                    rtlock2.lockInterruptibly();                    try{                        Thread.sleep(500);                    }catch (InterruptedException e){                    }                    rtlock1.lockInterruptibly();                }            }catch (InterruptedException e){                e.getMessage();            }finally {                if(rtlock1.isHeldByCurrentThread())                    rtlock1.unlock();                if(rtlock2.isHeldByCurrentThread())                    rtlock2.unlock();                System.out.println("线程退出:" + Thread.currentThread().getName());            }        }    });    public static void main(String[] args) throws InterruptedException{        /*ReentrantDemo rtd = new ReentrantDemo();        Thread t1 = new Thread(rtd.t);        Thread t2 = new Thread(rtd.t);        Thread t3 = new Thread(rtd.t);        t1.start();        t2.start();        t3.start();        t1.join();        t2.join();        t3.join();        System.out.println(count);*/        /*        避免死锁的方法：1. 外部方法，通过中断避免死锁                      2. 锁申请限时等待                      3. ReentrantLock.tryLock()         */        ReentrantDemo rtd1 = new ReentrantDemo(1);        ReentrantDemo rtd2 = new ReentrantDemo(1);        Thread t1 = new Thread(rtd1.t);        Thread t2 = new Thread(rtd2.t);        t1.start();        t2.start();        Thread.sleep(1000);        //t2中断  释放资源        t2.interrupt();    }}