java为什么不支持线程。isInterrupted（）即使在调用线程后也返回false。currentThread（）。中断（）

Question

当我运行这个测试时，为什么sleepThread.isInterrupted()总是返回false

（我必须执行Thread.currentThread().interrupt()以在捕获InterruptedException时设置中断标志）

@Test
public void t() {
    Thread sleepThread = new Thread() {
        @Override
        public void run() {
            try {
                Thread.sleep(5 * 1000);
            } catch (InterruptedException e) {
                System.out.println("have been interruptted....");
                e.printStackTrace();

                Thread.currentThread().interrupt();

                // in here this.isInterrupted() will return true
                System.out.println("now , instant interrupt flag : " 
                + this.isInterrupted());
            }
        }
    };
    sleepThread.start();

    try {
        sleepThread.interrupt();
        Thread.sleep(2 * 1000);

        // in here ,why sleepThread.isInterrupted() return false ?
        System.out.println("sleep thread interrupt flag : " 
        + sleepThread.isInterrupted());
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
}

这是输出：

have been interruptted
now , instant interrupt flag : true
java.lang.InterruptedException: sleep interrupted
   at java.lang.Thread.sleep(Native Method)
   at com.roundwith.concurrent.Interrupt_Test$1.run(Interrupt_Test.java:15)
sleep thread interrupt flag : false

Answer 1

这是因为当最后一句话到达的时候

System.out.println("sleep thread interrupt flag : " + sleepThread.isInterrupted());

线会死的

尝试删除主线程中的2秒睡眠，你会看到不同之处（尝试几次运行，它可能仍然打印为false，但至少主线程有机会看到另一个线程处于活动状态）

Answer 2

尝试改变

Thread.sleep(2 * 1000);

到

//Thread.sleep(2 * 1000);