Executor

Executor<wbr style="line-height:25px"><br style="line-height:25px"> java.util.concurrent<br style="line-height:25px"> 接口Executor<br style="line-height:25px"> 所有已知子接口：<br style="line-height:25px"> ExecutorService,ScheduledExecutorService<br style="line-height:25px"> 所有已知实现类：<br style="line-height:25px"> AbstractExecutorService,<span style="line-height:25px"><wbr style="line-height:25px"></wbr></span><span style="color:#ff9900; line-height:25px">ScheduledThreadPoolExecutor</span><span style="line-height:25px">,</span><span style="color:#ff9900; line-height:25px">ThreadPoolExecutor</span><wbr style="line-height:25px"><br style="line-height:25px"> 它用于执行Runnable任务。此接口提供一种将任务提交与每个任务将如何运行的机制（包括线程使用的细节、调度等）分离开来的方法。<br style="line-height:25px"> 通常使用Executor而不是显式地创建线程。<br style="line-height:25px"> 例如，可能会使用以下方法，而不是为一组任务中的每个任务调用newThread(new(RunnableTask())).start()：<br style="line-height:25px"><span style="line-height:normal; color:rgb(51,51,51); font-family:arial,sans-serif; font-size:13px"></span> <pre class="prettyprint" style="line-height:inherit; padding-top:10px; padding-right:10px; padding-bottom:10px; padding-left:10px; border-top-width:1px; border-right-width:1px; border-bottom-width:1px; border-left-width:1px; border-top-style:solid; border-right-style:solid; border-bottom-style:solid; border-left-style:solid; border-top-color:rgb(204,204,204); border-right-color:rgb(204,204,204); border-bottom-color:rgb(204,204,204); border-left-color:rgb(204,204,204); color:rgb(0,112,0); font-family:monospace; background-color:rgb(250,250,250); margin-top:0px; margin-bottom:1em; margin-left:1em; overflow-x:auto; overflow-y:auto"><span style="line-height:23px; color:rgb(102,0,102)"><span class="typ" style="line-height:23px; color:rgb(102,0,102)">Executor</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> executor </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">=</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><em><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)">anExecutor</span></span></em><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">;</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)">executor</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">.</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)">execute</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">(</span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">new</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,0,102)"><span class="typ" style="line-height:23px; color:rgb(102,0,102)">RunnableTask1</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">());</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)">executor</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">.</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)">execute</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">(</span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">new</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,0,102)"><span class="typ" style="line-height:23px; color:rgb(102,0,102)">RunnableTask2</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">());</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"></span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">...</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"></span></span></pre> </wbr></wbr>...
不过，<wbr style="line-height:25px"><span style="color:#ff00ff; line-height:25px">Executo</span><span style="color:#003366; line-height:25px">r接口并没有严格地要求执行是异步的<wbr style="line-height:25px">。</wbr></span><br style="line-height:25px"> 因此执行程序可以在调用者的线程中立即运行已提交的任务：<br style="line-height:25px"><span style="color:#3366ff; line-height:25px"><span style="line-height:normal; color:rgb(51,51,51); font-family:arial,sans-serif; font-size:13px"></span></span> <pre class="prettyprint" style="line-height:inherit; padding-top:10px; padding-right:10px; padding-bottom:10px; padding-left:10px; border-top-width:1px; border-right-width:1px; border-bottom-width:1px; border-left-width:1px; border-top-style:solid; border-right-style:solid; border-bottom-style:solid; border-left-style:solid; border-top-color:rgb(204,204,204); border-right-color:rgb(204,204,204); border-bottom-color:rgb(204,204,204); border-left-color:rgb(204,204,204); color:rgb(0,112,0); font-family:monospace; background-color:rgb(250,250,250); margin-top:0px; margin-bottom:1em; margin-left:1em; overflow-x:auto; overflow-y:auto"><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">class</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,0,102)"><span class="typ" style="line-height:23px; color:rgb(102,0,102)">DirectExecutor</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">implements</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,0,102)"><span class="typ" style="line-height:23px; color:rgb(102,0,102)">Executor</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">{</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">public</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">void</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> execute</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">(</span></span><span style="line-height:23px; color:rgb(102,0,102)"><span class="typ" style="line-height:23px; color:rgb(102,0,102)">Runnable</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> r</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">)</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">{</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> r</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">.</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)">run</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">();</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">}</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"></span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">}</span></span></pre> 更常见的是，任务是在某个不是调用者线程的线程中执行的。以下执行程序将为每个任务生成一个新线程。<br style="line-height:25px"><span style="color:#3366ff; line-height:25px"><span style="line-height:normal; color:rgb(51,51,51); font-family:arial,sans-serif; font-size:13px"></span></span> <pre class="prettyprint" style="line-height:inherit; padding-top:10px; padding-right:10px; padding-bottom:10px; padding-left:10px; border-top-width:1px; border-right-width:1px; border-bottom-width:1px; border-left-width:1px; border-top-style:solid; border-right-style:solid; border-bottom-style:solid; border-left-style:solid; border-top-color:rgb(204,204,204); border-right-color:rgb(204,204,204); border-bottom-color:rgb(204,204,204); border-left-color:rgb(204,204,204); color:rgb(0,112,0); font-family:monospace; background-color:rgb(250,250,250); margin-top:0px; margin-bottom:1em; margin-left:1em; overflow-x:auto; overflow-y:auto"><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"></span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">class</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,0,102)"><span class="typ" style="line-height:23px; color:rgb(102,0,102)">ThreadPerTaskExecutor</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">implements</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,0,102)"><span class="typ" style="line-height:23px; color:rgb(102,0,102)">Executor</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">{</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">public</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">void</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> execute</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">(</span></span><span style="line-height:23px; color:rgb(102,0,102)"><span class="typ" style="line-height:23px; color:rgb(102,0,102)">Runnable</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> r</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">)</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">{</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">new</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,0,102)"><span class="typ" style="line-height:23px; color:rgb(102,0,102)">Thread</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">(</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)">r</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">).</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)">start</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">();</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">}</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"></span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">}</span></span></pre> 许多Executor的实现都对调度任务的方式和时间强加了某种限制。以下执行程序使任务提交与第二个执行程序保持连续，这说明了一个复合执行程序。<br style="line-height:25px"><span style="line-height:25px"><wbr style="line-height:25px">示例1</wbr></span><br style="line-height:25px"><span style="color:#3366ff; line-height:25px"><span style="line-height:normal; color:rgb(51,51,51); font-family:arial,sans-serif; font-size:13px"></span></span> <pre class="prettyprint" style="line-height:inherit; padding-top:10px; padding-right:10px; padding-bottom:10px; padding-left:10px; border-top-width:1px; border-right-width:1px; border-bottom-width:1px; border-left-width:1px; border-top-style:solid; border-right-style:solid; border-bottom-style:solid; border-left-style:solid; border-top-color:rgb(204,204,204); border-right-color:rgb(204,204,204); border-bottom-color:rgb(204,204,204); border-left-color:rgb(204,204,204); color:rgb(0,112,0); font-family:monospace; background-color:rgb(250,250,250); margin-top:0px; margin-bottom:1em; margin-left:1em; overflow-x:auto; overflow-y:auto"><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"></span></span><code style="line-height:1em; color:rgb(0,112,0); font-family:monospace"><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">class</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,0,102)"><span class="typ" style="line-height:23px; color:rgb(102,0,102)">SerialExecutor</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">implements</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,0,102)"><span class="typ" style="line-height:23px; color:rgb(102,0,102)">Executor</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">{</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">final</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,0,102)"><span class="typ" style="line-height:23px; color:rgb(102,0,102)">Queue</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> tasks </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">=</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">new</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,0,102)"><span class="typ" style="line-height:23px; color:rgb(102,0,102)">ArrayDeque</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">();</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">final</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,0,102)"><span class="typ" style="line-height:23px; color:rgb(102,0,102)">Executor</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> executor</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">;</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,0,102)"><span class="typ" style="line-height:23px; color:rgb(102,0,102)">Runnable</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> active</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">;</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,0,102)"><span class="typ" style="line-height:23px; color:rgb(102,0,102)">SerialExecutor</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">(</span></span><span style="line-height:23px; color:rgb(102,0,102)"><span class="typ" style="line-height:23px; color:rgb(102,0,102)">Executor</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> executor</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">)</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">{</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">this</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">.</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)">executor </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">=</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> executor</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">;</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span></code><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">public</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">synchronized</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">void</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> execute</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">(</span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">final</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,0,102)"><span class="typ" style="line-height:23px; color:rgb(102,0,102)">Runnable</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> r</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">)</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">{</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> tasks</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">.</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)">offer</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">(</span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">new</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,0,102)"><span class="typ" style="line-height:23px; color:rgb(102,0,102)">Runnable</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">()</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">{</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">public</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">void</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> run</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">()</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">{</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">try</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">{</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> r</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">.</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)">run</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">();</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">}</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">finally</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">{</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> scheduleNext</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">();</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">}</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">}</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">});</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">if</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">(</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)">active </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">==</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">null</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">)</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">{</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> scheduleNext</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">();</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">}</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">}</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">protected</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">synchronized</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">void</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> scheduleNext</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">()</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">{</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">if</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">((</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)">active </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">=</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> tasks</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">.</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)">poll</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">())</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">!=</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(0,0,136)"><span class="kwd" style="line-height:23px; color:rgb(0,0,136)">null</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">)</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">{</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> executor</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">.</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)">execute</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">(</span></span><span style="line-height:23px; color:rgb(0,0,0)"><span class="pln" style="line-height:23px; color:rgb(0,0,0)">active</span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">);</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">}</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"> </span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">}</span></span><span style="line-height:23px; color:rgb(0,0,0)"><br style="line-height:23px"><span class="pln" style="line-height:23px; color:rgb(0,0,0)"></span></span><span style="line-height:23px; color:rgb(102,102,0)"><span class="pun" style="line-height:23px; color:rgb(102,102,0)">}}</span></span></pre> <span style="line-height:25px"><wbr style="line-height:25px">注意1</wbr></span><wbr style="line-height:25px">:许多Executor的实现都对调度任务的方式和时间强加了某种限制。<br style="line-height:25px"> 所以如果我们想要任务<wbr style="line-height:25px"><span style="color:#000080; line-height:25px">一个一个的顺序被执行，可以才采用示例1（SerialExecutor）的方式<wbr style="line-height:25px">。</wbr></span><br style="line-height:25px"> 此包中提供的Executor实现都实现了ExecutorService，ExecutorService是Executor的一个子类，它提供了一个使用更广泛的接口。<br style="line-height:25px"> 比如ThreadPoolExecutor类就同时实现了Executor和ExecutorService接口，它提供一个可扩展的线程池实现。<br style="line-height:25px"> Executors类为创建这些Executor提供了便捷的工厂方法。<br style="line-height:25px"><span style="line-height:25px">注意</span>：Executor的直接子接口ExecutorService,ExecutorService的直接子接口（Executor的间接子接口）ScheduledExecutorService提供了更为广泛使用的接口。<br style="line-height:25px"> 关于ExecutorService的更多知识请参阅《<strong><a title="阅读全文" target="_blank" href="http://hubingforever.blog.163.com/blog/static/17104057920109544134947/" style="color:rgb(207,121,28); line-height:25px; text-decoration:none">ExecutorService</a></strong>》,<br style="line-height:25px"> 关于ScheduledExecutorService的更多知识请参考《<strong><a title="阅读全文" target="_blank" href="http://hubingforever.blog.163.com/blog/static/17104057920109544814639/" style="color:rgb(207,121,28); line-height:25px; text-decoration:none">ScheduledExecutorService</a></strong>》。<br style="line-height:25px"> 内存一致性效果：线程中将Runnable对象提交到Executor之前的操作happen-before其执行开始（可能在另一个线程中）。<br style="line-height:25px"><span style="line-height:25px"><wbr style="line-height:25px">主要方法</wbr></span><wbr style="line-height:25px">：<br style="line-height:25px"><span style="color:#993300; line-height:25px">void</span><span style="color:#ff6600; line-height:25px">execute</span>(Runnablecommand)<br style="line-height:25px"> 在未来某个时间执行给定的命令。该命令可能在新的线程、已入池的线程或者正调用的线程中执行，这由Executor实现决定。<br style="line-height:25px"> 参数：<br style="line-height:25px"> command-可运行的任务<br style="line-height:25px"> 抛出：<br style="line-height:25px"> RejectedExecutionException-如果不能接受执行此任务。<br style="line-height:25px"> NullPointerException-如果命令为null<br style="line-height:25px"><span style="line-height:25px"><wbr style="line-height:25px">注意</wbr></span><wbr style="line-height:25px">：该方法是它自己<wbr style="line-height:25px"><span style="color:#000080; line-height:25px">唯一</span><wbr style="line-height:25px">的方法。 </wbr></wbr></wbr></wbr></wbr></wbr></wbr>