线程中断的概念
java中线程中断是一种协作机制
通过中断并不能直接终止线程的运作
需要被中断的线程自己处理中断.
每个线程都有一个boolean类型的标志位，代表线程是否中断；
线程1想中断线程2，线程1只需要设置线程2的中断标识位等于true即可；
线程2在合适的时候处理中断请求，甚至线程2可以选择不处理中断请求；
结论：设置线程中断后，被中断的线程不是立即停止运行状态。
线程中断的相关方法
1：public static boolean interrupted()
/**
* Tests whether the current thread has been interrupted. The
* <i>interrupted status</i> of the thread is cleared by this method. In
* other words, if this method were to be called twice in succession, the
* second call would return false (unless the current thread were
* interrupted again, after the first call had cleared its interrupted
* status and before the second call had examined it).
*
* <p>A thread interruption ignored because a thread was not alive
* at the time of the interrupt will be reflected by this method
* returning false.
*
* @return <code>true</code> if the current thread has been interrupted;
* <code>false</code> otherwise.
* @see #isInterrupted()
* @revised 6.0
*/
public static boolean interrupted() {
return currentThread().isInterrupted(true);
}
测试当前线程是否已中断。线程的中断状态由该方法清除。
如果连续调用两次该方法，则第二次调用将返回false，在第一次调用已清除了其中中断状态，且第二次调用检验中断状态前，可以对当前线程再次中断。
2：public boolean isInterrupted()
/**
* Tests whether this thread has been interrupted. The <i>interrupted
* status</i> of the thread is unaffected by this method.
*
* <p>A thread interruption ignored because a thread was not alive
* at the time of the interrupt will be reflected by this method
* returning false.
*
* @return <code>true</code> if this thread has been interrupted;
* <code>false</code> otherwise.
* @see #interrupted()
* @revised 6.0
*/
public boolean isInterrupted() {
return isInterrupted(false);
}
测试线程是否已经中断，线程的中断状态不受该方法的影响。
3：public void interrupt()
public void interrupt() {
if (this != Thread.currentThread())
checkAccess();
synchronized (blockerLock) {
Interruptible b = blocker;
if (b != null) {
interrupt0(); // Just to set the interrupt flag
b.interrupt(this);
return;
}
}
interrupt0();
}
这个方法是唯一能将中断状态设置为true的方法，静态方法interrupted()会将当前线程的状态清除。
方法中会抛出 InterruptedException 则表示该方法是可中断
常见的抛出InterruptedException 的方法：
object.wait();
Thread.sleep();
BlockQueue.put();
BlockQueue.take();
参考书籍：《并发编程的实战》
