Java 并发编程之深入理解"锁可中断"机制

import java.util.concurrent.locks.ReentrantLock;
public class InterruptibleLockDemo {
    private static final ReentrantLock lock = new ReentrantLock();
    public static void main(String[] args) throws InterruptedException {
        // 1. 线程 A 获取锁，并长时间持有
        Thread threadA = new Thread(() -> {
            lock.lock();
            try {
                System.out.println("Thread A: 获取了锁，开始执行长任务...");
                Thread.sleep(100000); // 模拟长时间占用
            } catch (InterruptedException e) {
                e.printStackTrace();
            } finally {
                lock.unlock();
            }
        });
        // 2. 线程 B 尝试获取锁，使用 lockInterruptibly()
        Thread threadB = new Thread(() -> {
            try {
                System.out.println("Thread B: 尝试获取锁...");
                // 关键点：使用可中断的获取锁方法
                lock.lockInterruptibly(); 
                try {
                    System.out.println("Thread B: 成功获取锁！");
                } finally {
                    lock.unlock();
                }
            } catch (InterruptedException e) {
                // 3. 捕获中断异常
                System.out.println("Thread B: 等待锁时被中断了！" + e.getMessage());
            }
        });
        threadA.start();
        Thread.sleep(1000); // 确保 A 先拿到锁
        threadB.start();
        Thread.sleep(1000); // 确保 B 进入等待状态
        // 4. 主线程中断线程 B
        System.out.println("Main: 准备中断 Thread B...");
        threadB.interrupt();
    }
}

// 简化的逻辑演示
Thread worker = new Thread(() -> {
    lock.lock(); // 获取锁
    try {
        // 执行任务，即使此时被 interrupt，也会继续执行
        for (int i = 0; i < 3; i++) {
            if (Thread.interrupted()) {
                System.out.println("Worker: 发现中断标志，但我持有锁，继续执行...");
            }
            System.out.println("Worker: 执行步骤 " + i);
        }
    } finally {
        lock.unlock(); // 必须手动释放
        System.out.println("Worker: 锁已释放。");
    }
});

boolean locked = false;
try {
    lock.lockInterruptibly();
    locked = true; // 标记锁获取成功
    // --- 业务逻辑 ---
} catch (InterruptedException e) {
    // 处理中断
    Thread.currentThread().interrupt(); // 恢复中断状态，不要吞掉中断
} finally {
    if (locked) {
        lock.unlock(); // 只有获取成功才解锁
    }
}