Java学习，查看线程是否存活

Java可以使用Thread类，isAlive()方法检查线程是否仍然存活。isAlive()方法返回一个布尔值，如果线程仍然在运行，则返回true；如果线程已经死亡（完成执行或未启动过），则返回false。

示例：

public class ThreadAliveExample { 
    public static void main(String[] args) throws InterruptedException {
        // 创建线程
        Thread myThread = new Thread(() -> {
            try {
                // 线程休眠
                Thread.sleep(3000);
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt(); // 恢复中断状态
            }
            System.out.println("Thread has finished execution.");
        });
 
        // 启动线程
        myThread.start();
 
        // 检查线程是否存活
        System.out.println("Is thread alive? " + myThread.isAlive());
 
        // 等待一段时间
        Thread.sleep(1000);
        System.out.println("Is thread still alive after 1 second? " + myThread.isAlive());
 
        // 再等待足够长的时间，确保线程完成执行
        Thread.sleep(3000);
        System.out.println("Is thread alive after thread has finished? " + myThread.isAlive());
    }
}

运行结果：

Is thread alive? true
Is thread still alive after 1 second? true
Thread has finished execution.
Is thread alive after thread has finished? false