深入分析Java线程中断机制

尊重原创：http://blog.csdn.net/yuanzeyao/article/details/47186167

Thread.interrupt真的能中断线程吗

在平时的开发过程中，相信都会使用到多线程，在使用多线程时，大家也会遇到各种各样的问题，今天我们就来说说一个多线程的问题——线程中断。在java中启动线程非常容易，大多数情况下我是让一个线程执行完自己的任务然后自己停掉，但是有时候我们需要取消某个操作，比如你在网络下载时，有时候需要取消下载。实现线程的安全中断并不是一件容易的事情，因为Java并不支持安全快速中断线程的机制，这里估计很多同学就会说了，java不是提供了Thread.interrupt 方法中断线程吗，好吧，我们今天就从这个方法开始说起。 
但是调用此方法线程真的会停止吗？我们写个demo看看就知道了。

<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Main</span> {</span>
  <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> String TAG = <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Main"</span>;
  <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">main</span>(String[] args) {
    Thread t=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Thread(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> NRunnable());
    t.start();
    System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"is start......."</span>);
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {
      Thread.sleep(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">3000</span>);
    } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (InterruptedException e) {

    }

    t.interrupt();
    System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"is interrupt......."</span>);

  }

  <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">NRunnable</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">implements</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Runnable</span>
  {</span>

    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">run</span>() {
      <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">while</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>)
      {
        System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"我没有种中断"</span>);
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {
          Thread.sleep(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1000</span>);
        } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (InterruptedException e) {

        }
      }
    }

  }
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li></ul>

如果interrutp方法能够中断线程，那么在打印了is interrupt…….之后应该是没有log了，我们看看执行结果吧

<code class="hljs lasso has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">is start<span class="hljs-attribute" style="box-sizing: border-box;">...</span><span class="hljs-attribute" style="box-sizing: border-box;">...</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>
我没有种中断
我没有种中断
我没有种中断
我没有种中断
我没有种中断
is interrupt<span class="hljs-attribute" style="box-sizing: border-box;">...</span><span class="hljs-attribute" style="box-sizing: border-box;">...</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>
我没有种中断
我没有种中断
我没有种中断
我没有种中断
我没有种中断
<span class="hljs-attribute" style="box-sizing: border-box;">...</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li></ul>

通过结果可以发现子线程并没有中断 
所以 Thread.interrupt() 方法并不能中断线程，该方法仅仅告诉线程外部已经有中断请求，至于是否中断还取决于线程自己。在Thread类中除了interrupt（） 方法还有另外两个非常相似的方法：interrupted 和 isInterrupted 方法，下面来对这几个方法进行说明：

• interrupt 此方法是实例方法，用于告诉此线程外部有中断请求，并且将线程中的中断标记设置为true
• interrupted 此方法是类方法，测试当前线程是否已经中断。线程的中断状态 由该方法清除。换句话说，如果连续两次调用该方法，则第二次调用将返回 false（在第一次调用已清除了其中断状态之后，且第二次调用检验完中断状态前，当前线程再次中断的情况除外）。
• isInterrupted 此方法是实例方法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。 线程中断被忽略，因为在中断时不处于活动状态的线程将由此返回 false 的方法反映出来

处理线程中断的常用方法

设置取消标记

还是用上面的例子，只不过做了些修改

<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">main</span>(String[] args) {
    NRunnable run=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> NRunnable();
    Thread t=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Thread(run);
    t.start();
    System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"is start......."</span>);
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {
      Thread.sleep(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">3000</span>);
    } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (InterruptedException e) {

    }
    run.cancel();
    System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"cancel ..."</span>+System.currentTimeMillis());
  }

  <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">NRunnable</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">implements</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Runnable</span>
  {</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> isCancel=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>;

    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">run</span>() {
      <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">while</span>(!isCancel)
      {
        System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"我没有种中断"</span>);
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {
          Thread.sleep(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">10000</span>);
        } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (InterruptedException e) {

        }
      }
      System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"我已经结束了..."</span>+System.currentTimeMillis());
    }

    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">cancel</span>()
    {
      <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.isCancel=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>;
    }

  }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li></ul>

执行结果如下：

<code class="hljs lasso has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">is start<span class="hljs-attribute" style="box-sizing: border-box;">...</span><span class="hljs-attribute" style="box-sizing: border-box;">...</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>
我没有种中断
cancel <span class="hljs-attribute" style="box-sizing: border-box;">...</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1438396915809</span>
我已经结束了<span class="hljs-attribute" style="box-sizing: border-box;">...</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1438396922809</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li></ul>

通过结果，我们发现线程确实已经中断了，但是细心的同学应该发现了一个问题，调用cancel方法和最后线程执行完毕之间隔了好几秒的时间，也就是说线程不是立马中断的，我们下面来分析一下原因： 
子线程退出的条件是while循环结束，也就是cancel标示设置为true，但是当我们调用cancel方法将calcel标记设置为true时，while循环里面有一个耗时操作(sleep方法模拟)，只有等待耗时操作执行完毕后才会去检查这个标记，所以cancel方法和线程退出中间有时间间隔。

通过interrupt 和 isinterrupt 方法来中断线程

<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">main</span>(String[] args) {
    Thread t=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> NThread();
    t.start();
    System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"is start......."</span>);
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {
      Thread.sleep(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">3000</span>);
    } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (InterruptedException e) {

    }
    System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"start interrupt..."</span>+System.currentTimeMillis());
    t.interrupt();
    System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"end interrupt ..."</span>+System.currentTimeMillis());
  }

  <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">NThread</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">extends</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Thread</span>
  {</span>

    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">run</span>() {
      <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">while</span>(!<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.isInterrupted())
      {
        System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"我没有种中断"</span>);
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {
          Thread.sleep(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">10000</span>);
        } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (InterruptedException e) {
          Thread.currentThread().interrupt();
        }
      }
      System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"我已经结束了..."</span>+System.currentTimeMillis());
    }

  }
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li></ul>

运行结果如下：

<code class="hljs lasso has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">is start<span class="hljs-attribute" style="box-sizing: border-box;">...</span><span class="hljs-attribute" style="box-sizing: border-box;">...</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>
我没有种中断
start interrupt<span class="hljs-attribute" style="box-sizing: border-box;">...</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1438398800110</span>
我已经结束了<span class="hljs-attribute" style="box-sizing: border-box;">...</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1438398800110</span>
end interrupt <span class="hljs-attribute" style="box-sizing: border-box;">...</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1438398800110</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li></ul>

这次是立马中断的，但是这种方法是由局限性的，这种方法仅仅对于会抛出InterruptedException 异常的任务时有效的，比如java中的sleep、wait 等方法，对于不会抛出这种异常的任务其效果其实和第一种方法是一样的，都会有延迟性，这个例子中还有一个非常重要的地方就是cache语句中，我们调用了Thread.currentThread().interrupt() 我们把这句代码去掉，运行你会发现这个线程无法终止，因为在抛出InterruptedException 的同时，线程的中断标志被清除了，所以在while语句中判断当前线程是否中断时，返回的是false.针对InterruptedException 异常，我想说的是：一定不能再catch语句块中什么也不干，如果你实在不想处理，你可以将异常抛出来，让调用抛异常的方法也成为一个可以抛出InterruptedException 
的方法，如果自己要捕获此异常，那么最好在cache语句中调用 Thread.currentThread().interrupt(); 方法来让高层只要中断请求并处理该中断。

对于上述两种方法都有其局限性，第一种方法只能处理那种工作量不大，会频繁检查循环标志的任务，对于第二种方法适合用于抛出InterruptedException的代码。也就是说第一种和第二种方法支持的是支持中断的线程任务，那么不支持中断的线程任务该怎么做呢。 
例如 如果一个线程由于同步进行I／Ｏ操作导致阻塞，中断请求不会抛出InterruptedException　，我们该如何中断此线程呢。

处理不支持中断的线程中断的常用方法

改写线程的interrupt方法

<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ReaderThread</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">extends</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Thread</span>
 {</span>
   <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> BUFFER_SIZE=<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">512</span>;
   Socket socket;
   InputStream is;

   <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-title" style="box-sizing: border-box;">ReaderThread</span>(Socket socket) <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throws</span> IOException
   {
     <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.socket=socket;
     is=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.socket.getInputStream();
   }

   <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
  <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">interrupt</span>() {
     <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span>
     {
       socket.close();
     }<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span>(IOException e)
     {

     }<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">finally</span>
     {
       <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>.interrupt();
     }
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>.interrupt();
  }
   <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
  <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">run</span>() {
     <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span>
     {
       <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">byte</span>[]buf=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">byte</span>[BUFFER_SIZE];
       <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">while</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>)
       {
         <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> count=is.read(buf);
         <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(count<<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>)
           <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">break</span>;
         <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(count><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>)
         {

         }
       }
     }<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span>(IOException e)
     {

     }
  }
 }
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li><li style="box-sizing: border-box; padding: 0px 5px;">44</li><li style="box-sizing: border-box; padding: 0px 5px;">45</li><li style="box-sizing: border-box; padding: 0px 5px;">46</li><li style="box-sizing: border-box; padding: 0px 5px;">47</li><li style="box-sizing: border-box; padding: 0px 5px;">48</li></ul>

例如在上面的例子中，改写了Thread的interrupt 方法，当调用interrupt 方法时，会关闭socket，如果此时read方法阻塞，那么会抛出IOException 此时线程任务也就结束了。

以上方法是通过改写线程的interrupt 方法实现，那么对于使用线程池的任务该怎么中断呢。

改写线程池的newTaskFor方法

通常我们向线程池中加入一个任务采用如下形式：

<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">Future<?> future=executor.submit(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Runnable(){
      <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
      <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">run</span>() {

      }
    });</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li></ul>

取消任务时，调用的是future的cancel方法，其实在cancel方法中调用的是线程的interrupt方法。所以对于不支持中断的任务cancel也是无效的，下面我们看看submit方法里面干了上面吧

<code class="hljs cs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> Future<?> <span class="hljs-title" style="box-sizing: border-box;">submit</span>(Runnable task) {
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (task == <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throw</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> NullPointerException();
        RunnableFuture<Void> ftask = newTaskFor(task, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>);
        execute(ftask);
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> ftask;
    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li></ul>

这里调用的是AbstractExecutorService 的newTaskFor方法，那么我们能不能改写ThreadPoolExecutor的newTaskFor方法呢，接下来看我在处理吧 
定义一个基类，所有需要取消的任务继承这个基类

<code class="hljs axapta has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">interface</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">CancelableRunnable</span><<span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">T</span>> <span class="hljs-inheritance" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">extends</span></span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Runnable</span> {</span>

  <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> cancel();
  <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> RunnableFuture<T> newTask();

}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li></ul>

将上面的ReaderThread改为继承这个类

<code class="hljs axapta has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ReaderThread</span> <span class="hljs-inheritance" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">implements</span></span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">CancelableRunnable</span><<span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Void</span>>
  {</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> BUFFER_SIZE=<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">512</span>;
    Socket socket;
    InputStream is;

    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> ReaderThread(Socket socket) throws IOException
    {
      <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.socket=socket;
      is=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.socket.getInputStream();
    }


    @Override
   <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> run() {
      <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span>
      {
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">byte</span>[]buf=<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">byte</span>[BUFFER_SIZE];
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">while</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>)
        {
          <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">count</span>=is.read(buf);
          <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">count</span><<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>)
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">break</span>;
          <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">count</span>><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>)
          {

          }
        }
      }<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span>(IOException e)
      {

      }
   }

    @Override
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> cancel() {
      <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {
        socket.close();
      } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (IOException e) {

      }
    }

    @Override
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> RunnableFuture<Void> newTask() {
      <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> FutureTask<Void>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>)
          {
            @Override
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> cancel(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> mayInterruptIfRunning) {
              <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>.cancel(mayInterruptIfRunning);
              <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(ReaderThread.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span> instanceof CancelableRunnable))
              {
                ((CancelableRunnable)(ReaderThread.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>)).cancel();
              }<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span>
              {
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>.cancel(mayInterruptIfRunning);
              }
            }
          };

    }
 }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li><li style="box-sizing: border-box; padding: 0px 5px;">44</li><li style="box-sizing: border-box; padding: 0px 5px;">45</li><li style="box-sizing: border-box; padding: 0px 5px;">46</li><li style="box-sizing: border-box; padding: 0px 5px;">47</li><li style="box-sizing: border-box; padding: 0px 5px;">48</li><li style="box-sizing: border-box; padding: 0px 5px;">49</li><li style="box-sizing: border-box; padding: 0px 5px;">50</li><li style="box-sizing: border-box; padding: 0px 5px;">51</li><li style="box-sizing: border-box; padding: 0px 5px;">52</li><li style="box-sizing: border-box; padding: 0px 5px;">53</li><li style="box-sizing: border-box; padding: 0px 5px;">54</li><li style="box-sizing: border-box; padding: 0px 5px;">55</li><li style="box-sizing: border-box; padding: 0px 5px;">56</li><li style="box-sizing: border-box; padding: 0px 5px;">57</li><li style="box-sizing: border-box; padding: 0px 5px;">58</li><li style="box-sizing: border-box; padding: 0px 5px;">59</li><li style="box-sizing: border-box; padding: 0px 5px;">60</li><li style="box-sizing: border-box; padding: 0px 5px;">61</li><li style="box-sizing: border-box; padding: 0px 5px;">62</li></ul>

当你调用future的cancel的方法时，它会关闭socket，最终导致read方法异常，从而终止线程任务。