Java 正确终止线程的方法

public class TerminableTaskRunner {
    // 存储要执行的任务
    private final BlockingQueue<Runnable> tasks;
    // 线程终止标志
    private volatile boolean terminated;
    // 剩余的任务数
    private final AtomicInteger count;
    // 实际执行任务的线程
    private volatile Thread workThread;
 
    public TerminableTaskRunner(int capacity) {
        this.tasks = new LinkedBlockingDeque<>(capacity);
        this.count = new AtomicInteger(0);
        this.workThread = new WorkThread();
        workThread.start();
    }
 
    public void submit(Runnable task) {
        this.tasks.add(task);
        this.count.incrementAndGet();
    }
 
    public void shutdown() {
        terminated = true; // 线程终止标志，由于中断标志可能会被覆盖，所以需要自己创建一个标志
        if (workThread != null)
            workThread.interrupt(); // 唤醒线程
    }
 
    private class WorkThread extends Thread {
        @Override
        public void run() {
            Runnable task;
            try {
                while (!terminated || tasks.size() >= 1) {
                    task = tasks.take();
                    try {
                        task.run(); // 可能会清空当前线程的中断标记，如task.run()在内部调用的阻塞方法抛出了InterruptedException
                    } catch (Throwable e) {
                        e.printStackTrace();
                    }
                    count.decrementAndGet();
                }
            } catch (InterruptedException e) {
                // 一旦调用shutdown且tasks.take()阻塞住，就抛出该异常，没有任务要执行，直接终止
                workThread = null;
            }
        }
    }
 
    public static void main(String[] args) {
        TerminableTaskRunner taskRunner = new TerminableTaskRunner(4);
        for (int i = 0; i < 4; i++) {
            taskRunner.submit(()->{
                try {
                    TimeUnit.SECONDS.sleep(1);
                } catch (InterruptedException e) {
                    System.out.println("客户端调用了 shutdown 方法");
                }
            });
        }
        taskRunner.shutdown();
 
    }
}