线程不能被interrupt中断

[datadev_sh]

如下代码，main方法中的休眠时间长短，会影响到是否能被中断，这是为什么？

import java.util.concurrent.locks.ReentrantLock;

public class ReentrantLockDemo implements Runnable {

	private static ReentrantLock lock1 = new ReentrantLock();
	private static ReentrantLock lock2 = new ReentrantLock();
	int lock;

	public ReentrantLockDemo(int lock) {
		this.lock = lock;
	}

	@Override
	public void run() {
		try {
			if (lock == 1) {
				lock1.lockInterruptibly();
				try {
					Thread.sleep(500);
				} catch (Exception e) {

				}
				lock2.lockInterruptibly();
			} else {
				lock2.lockInterruptibly();
				try {
					Thread.sleep(500);
				} catch (Exception e) {

				}
				lock1.lockInterruptibly();
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (lock1.isHeldByCurrentThread())
				lock1.unlock();
			if (lock2.isHeldByCurrentThread())
				lock2.unlock();
			System.out.println(Thread.currentThread().getName() + "退出");
		}
	}

	public static void main(String[] args) throws Exception {
		ReentrantLockDemo r1 = new ReentrantLockDemo(1);
		ReentrantLockDemo r2 = new ReentrantLockDemo(2);

		Thread t1 = new Thread(r1, "t1");
		Thread t2 = new Thread(r2, "t2");
		t1.start();
		t2.start();
		Thread.sleep(100);
		t2.interrupt();
	}
}

当休眠100毫秒是，发送死锁。当不休眠，或者休眠1000毫秒时，程序可以正常结束。

[soton_dolphin]

多加入一些注释，再用不同的时间让主线程休眠，你就能发现问题了。

import java.util.concurrent.locks.ReentrantLock;

public class ReentrantLockDemo implements Runnable {
	 
    private static ReentrantLock lock1 = new ReentrantLock();
    private static ReentrantLock lock2 = new ReentrantLock();
    int lock;
 
    public ReentrantLockDemo(int lock) {
        this.lock = lock;
    }
 
    
    public static void main(String[] args) throws Exception {
        ReentrantLockDemo r1 = new ReentrantLockDemo(1);
        ReentrantLockDemo r2 = new ReentrantLockDemo(2);
 
        Thread t1 = new Thread(r1, "t1");
        Thread t2 = new Thread(r2, "t2");
        t1.start();
        t2.start();
        System.out.println("线程 " + Thread.currentThread().getName() + " 将会休眠1秒");
        Thread.sleep(1000);
        System.out.println("线程 " + Thread.currentThread().getName() + " 已经苏醒。");
        t1.interrupt();
    }

    @Override
	public void run() {
    	String currentThreadName = Thread.currentThread().getName();
    	System.out.println("线程 " + currentThreadName + " 正在执行.");
    	 try {
             if (lock == 1) {
                 lock1.lockInterruptibly();
                 System.out.println("lock1 在线程  " + currentThreadName + "获得锁。");
                 try {
                	 System.out.println("线程 " + currentThreadName + " 将会休眠0.5秒");
                     Thread.sleep(500);
                     System.out.println("线程 " + currentThreadName + " 已经苏醒.");
                 } catch (Exception e) {
                	 System.err.println("线程 " + currentThreadName + " 被打断.");
                 }
                 lock2.lockInterruptibly();
                 System.out.println("lock2 在线程 " + currentThreadName + "获得锁。");
             } else {
                 lock2.lockInterruptibly();
                 System.out.println("lock2 在线程 " + currentThreadName + "获得锁。");
                 try {
                	 System.out.println("线程 " + currentThreadName + " 将会休眠0.5秒");
                     Thread.sleep(500);
                     System.out.println("线程 " + currentThreadName + " 已经苏醒.");
                 } catch (Exception e) {
                	 System.err.println("线程 " + currentThreadName + " 被打断.");
                 }
                 lock1.lockInterruptibly();
                 System.out.println("lock1 is locked in " + currentThreadName);
             }
         } catch (Exception e) {
             e.printStackTrace();
         } finally {
             if (lock1.isHeldByCurrentThread()){
                 lock1.unlock();
                 System.out.println("lock1 在线程  " + currentThreadName + "解锁");
             }
             if (lock2.isHeldByCurrentThread()){
                 lock2.unlock();
                 System.out.println("lock2 在线程  " + currentThreadName + "解锁");
             }
             System.out.println(Thread.currentThread().getName() + "退出");
         }
		
	}
}

[datadev_sh]

sleep过程中被中断，没有finally块来释放锁。