JAVA线程的interrupt

public static boolean interrupted ()

public boolean isInterrupted ()

1. sleep() & interrupt()
     线程A 正在使用sleep()暂停着:  Thread.sleep(100000);
    如果要取消他的等待状态,可以在正在执行的线程里(比如这里是B)调用
        a.interrupt();
    令线程A放弃睡眠操作,这里a是线程A对应到的Thread实例
    当在sleep中时 线程被调用interrupt()时,就马上会放弃暂停的状态.并抛出 InterruptedException .丢出异常的,是A线程.
2. wait() & interrupt()
    线程A调用了wait()进入了等待状态,也可以用interrupt()取消.
    不过这时候要小心锁定的问题.线程在进入等待区, 会把锁定解除,当对等待中的线程调用 interrupt()时
    ,会 先重新获取锁定,再抛出异常.在获取锁定之前,是无法抛出异常的.
3. join() & interrupt()
    当线程以join()等待其他线程结束时,当它被调用interrupt()，它与sleep()时一样, 会马上跳到 catch 块里. 
    注意 ，是对谁调用interrupt()方法,一定是调用被阻塞线程的interrupt方法.如在线程a中调用来线程t.join().
    则a会等t执行完后在执行t.join后的代码,当在线程b中调用来 a.interrupt()方法,则会抛出InterruptedException，当然join()也就被取消了。
实例1：
     static void  interruptDemo()
    {
        Thread t1=new Thread(new InterruptDemoRunnable(),"first");
        Thread t2=new Thread(new InterruptDemoRunnable(t1),"second");
        t1.start();
        t2.start();
    }
class  InterruptDemoRunnable implements Runnable
{
    long id=0;
    static long count=0;
    Thread t;
    InterruptDemoRunnable()
    {
        this(null);
    }
    InterruptDemoRunnable(Thread t)
    {
        id=count++;
        this.t=t;
    }
    boolean blRun=true;
     public void  run()
    {    int cnt=0;
          while ( blRun)
        {
            if(t!=null)
            {
                if(cnt==2)
                {
                    t.interrupt();
                    if( t.isInterrupted())
                        System.out.println("set the thread "+t.getName()+" to be Interrupted");
                }
                    
            }
            else
            {    
                try
                {
                    Thread.sleep(1000);
                }
                catch(InterruptedException e)
                {
                    System.out.println("First Interrupted when sleep");
                    System.out.println( "Interrupted is "+Thread.interrupted());//@1
                }
                try
                {
                    Thread.sleep(1);
                }
                catch(InterruptedException e)
                {
                    System.out.println("second Interrupted when sleep");
                }
            }
            System.out.println(id+"run"+cnt);
            cnt++;
            if(cnt==5)
            {
                blRun=false;            
            }
        }
            System.out.println("thread:"+id+"exit");
    }
}
注意1:当线程A执行到wait(),sleep(),join()时,抛出InterruptedException后，中断状态已经被系统复位了。
线程AThread.interrupted()返回的是false
实例2：
     static void  interruptDemo()
    {
        Thread t1=new InterruptDemoThread();
        t1.setName("t1");
        Thread t2=new InterruptDemoThread(t1);
        t1.setName("t2");
        t1.start();
        t2.start();
    }
class  InterruptDemoThread extends Thread
{
    long id=0;
    static long count=0;
    Thread t;
    InterruptDemoThread()
    {
        this(null);
    }

    InterruptDemoThread(Thread t)
    {
        id=count++;
        this.t=t;
    }
    boolean blRun=true;
     public void  run()
    {    int cnt=0;
         while (blRun)
        {
            if(t!=null)
            {
                if(cnt==2)
                {
                    t.interrupt();
                    if( t.isInterrupted() )
                        System.out.println("set the thread "+t.getName()+" to be Interrupted");
                }
                    
            }
            else if( isInterrupted() )@1
            {    
                /*Thread.interrupted();//@2
                System.out.println("after interrupted(),the state of Interrupted is "+isInterrupted());*/
                try{
                    Thread.sleep(1);
                }
                catch(InterruptedException e)
                {
                    System.out.println("Interrupted when sleep");
                    System.out.println( "Interrupted is "+Thread.interrupted());
                }
            }
            Thread.yield();
            System.out.println(id+"run"+cnt);
            cnt++;
            if(cnt==5)
            {
                blRun=false;            
            }
        }
            System.out.println("thread:"+id+"exit");
    }
}
注意1:如果线程被调用了interrupt()，那么如果此次该线程并不在wait(),sleep(),join()时，
下次执行 wait(),sleep(),join()时，一样会抛出InterruptedException，当然抛出后该线程的中断状态也回被系统复位。
注意2:我们可以 手动的使用Thread.interrupted()来使当前线程的中断状态系统复位（即清除中断状态）