java interrupt()方法

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Thread.interrupt并不会中断一个正在运行的线程

package thread;class Test extends Thread {    boolean stop=false;    public static void main( String args[] ) throws Exception {        Test thread = new Test();        System.out.println( "Starting thread..." );        thread.start();        Thread.sleep( 3000 );        System.out.println( "Interrupting thread..." );        thread.interrupt();        Thread.sleep( 3000 );        System.out.println("Stopping application..." );        //System.exit(0);    }    public void run() {        while(!stop){            System.out.println( "Thread is running..." );            long time = System.currentTimeMillis();            while((System.currentTimeMillis()-time < 1000)) {            }        }        System.out.println("Thread exiting under request..." );    }}

控制台运行结果如下：

Starting thread...
Thread is running...
Thread is running...
Thread is running...
Thread is running...
Interrupting thread...
Thread is running...
Thread is running...

....

在Thread.interrupt()被调用后，线程仍然继续运行。

使用Thread.interrupt()中断线程

Thread.interrupt()方法不会中断一个正在运行的线程。这一方法实际上完成的是，在线程受到阻塞时抛出一个中断信号，这样线程就得以退出阻塞的状态。更确切的说，如果线程被Object.wait, Thread.join和Thread.sleep三种方法之一阻塞，那么，它将接收到一个中断异常（InterruptedException），从而提早地终结被阻塞状态。

因此，如果线程被上述几种方法阻塞，正确的停止线程方式是设置共享变量，并调用interrupt()（注意变量应该先设置）。如果线程没有被阻塞，这时调用interrupt()将不起作用；否则，线程就将得到异常（该线程必须事先预备好处理此状况），接着逃离阻塞状态。在任何一种情况中，最后线程都将检查共享变量然后再停止。

package thread;class Test extends Thread {    volatile boolean stop = false;    public static void main( String args[] ) throws Exception {        Test thread = new Test();        System.out.println( "Starting thread..." );        thread.start();        Thread.sleep( 3000 );        System.out.println( "Asking thread to stop..." );        thread.stop = true;//如果线程阻塞，将不会检查此变量        thread.interrupt();        Thread.sleep( 3000 );        System.out.println( "Stopping application..." );        //System.exit( 0 );    }    public void run() {        while ( !stop ) {            System.out.println( "Thread running..." );            try {                Thread.sleep( 1000 );            } catch ( InterruptedException e ) {                System.out.println( "Thread interrupted..." );            }        }        System.out.println( "Thread exiting under request..." );    }}

Thread.interrupt()被调用，线程便收到一个异常，于是逃离了阻塞状态并确定应该停止，运行结果：

Starting thread...
Thread running...
Thread running...
Thread running...
Asking thread to stop...
Thread interrupted...
Thread exiting under request...
Stopping application...

总结：

Thread.interrupt()并不会中断一个正在运行的线程。但是，如果线程被阻塞，就会抛出一个中断信号，这样线程就得以退出阻塞的状态，使阻塞状态的线程逃离阻塞状态

void interrupt():向线程发送中断。线程中断状态被设置为true.如果目前线程被一个sleep调用阻塞，那么抛出InterruptedException异常

static boolean interrupted():测试当前线程是否被中断。这是静态方法，调用会产生副作业，它将当前线程的中断状态重置为false

boolean isInterrupted（）：测试当前线程是否被中断，不改变中断状态

参考网址：

http://blog.csdn.net/wxwzy738/article/details/8516253

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