Question

我面临着奇怪的行为。所有来源都告诉您在捕获中断异常后恢复中断标志后需要调用Thread.currentThread（）。interrupt（）。但我尝试创建一个简单的应用程序，在进程中断后检查中断状态

public class Main {
    public static void main(String[] args) throws InterruptedException {
        Runnable r = () -> {
            try {
                Thread.sleep(100000);
            } catch (InterruptedException e) {
                System.out.println("interrupted exception is occurred");
                Thread.currentThread().interrupt();
                System.out.println("interrupt flag is updated:" + Thread.currentThread().isInterrupted());
            }
        };

        Thread thread = new Thread(r);
        thread.start();
        thread.interrupt();

        boolean interruptFlag;
        do {
            Thread.sleep(1000);
            interruptFlag = thread.isInterrupted();
            System.out.println("interrupt flag:" + interruptFlag + " isAlive:" + thread.isAlive());
        } while (!interruptFlag);
    }
}

如果你尝试运行它，那么你得到

interrupted exception is occurred
interrupt flag is updated:true
interrupt flag:false isAlive:false
interrupt flag:false isAlive:false
interrupt flag:false isAlive:false
interrupt flag:false isAlive:false
interrupt flag:false isAlive:false

它将无限运作。问题是为什么在线程死后iterrupt标志是错误的？

Answer 1

当您从主线程检查中断状态时，第二个线程已经死亡，因此返回false。尝试将Thread.sleep（1000）置于等待循环的末尾，您将在中断状态下看到true。

此行为未记录，因此很难说它是缺少文档还是现有实现的功能。私有原生布尔值的实现是inInterrupted（boolean ClearInterrupted）;方法需要检查多说。

类似的讨论：Thread.isInterrupted() returns false after thread has been terminated

java Thread＃isInterrupt对于死线程返回false

1 个答案: