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2.1 Ï̳߳ØÊÇʲô
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2.3¡¢ThreadPoolExecutor µÄºËÐIJÎÊý
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corePoolSize:the number of threads to keep in the pool, even if they are idle, unless {@code allowCoreThreadTimeOut} is set
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maximumPoolSize:the maximum number of threads to allow in the pool
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keepAliveTime:when the number of threads is greater than the core, this is the maximum time that excess idle threads will wait for new tasks before terminating.
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unit:the time unit for the {@code keepAliveTime} argument
µ¥Î»:keepAliveTime µÄʱ¼äµ¥Î»
workQueue:the queue to use for holding tasks before they are executed. This queue will hold only the {@code Runnable} tasks submitted by the {@code execute} method.
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threadFactory:the factory to use when the executor creates a new thread
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handler :the handler to use when execution is blocked because the thread bounds and queue capacities are reached
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3.1 ×ÜÌåÉè¼Æ
ThreadPoolExecutor ʵÏֵĶ¥²ã½Ó¿ÚÊÇ Executor,¶¥²ã½Ó¿ÚÖ»ÌṩÁËvoid execute(Runnable command);
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ExecutorService ½Ó¿ÚÔö¼ÓÁËһЩÄÜÁ¦:
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3.2 Ï̳߳ØÈçºÎά»¤×ÔÉí״̬
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ctl Õâ¸ö AtomicInteger ÀàÐÍ,ÊǶÔÏ̳߳صÄÔËÐÐ״̬ºÍÏ̳߳ØÖÐÓÐЧÏ̵߳ÄÊýÁ¿½øÐпØÖƵÄÒ»¸ö×Ö¶Î, Ëüͬʱ°üº¬Á½²¿·ÖµÄÐÅÏ¢:Ï̳߳صÄÔËÐÐ״̬ (runState) ºÍÏ̳߳ØÄÚÓÐЧÏ̵߳ÄÊýÁ¿ (workerCount),¸ß 3 λ±£´æ runState,µÍ 29 λ±£´æ workerCount,Á½¸ö±äÁ¿Ö®¼ä»¥²»¸ÉÈÅ¡£ÓÃÒ»¸ö±äÁ¿È¥´æ´¢Á½¸öÖµ,¿É±ÜÃâÔÚ×öÏà¹Ø¾ö²ßʱ,³öÏÖ²»Ò»ÖµÄÇé¿ö,²»±ØΪÁËά»¤Á½ÕßµÄÒ»ÖÂ,¶øÕ¼ÓÃËø×ÊÔ´¡£Í¨¹ýÔĶÁÏ̳߳ØÔ´´úÂëÒ²¿ÉÒÔ·¢ÏÖ,¾³£³öÏÖҪͬʱÅжÏÏ̳߳ØÔËÐÐ״̬ºÍÏß³ÌÊýÁ¿µÄÇé¿ö¡£Ï̳߳ØÒ²ÌṩÁËÈô¸É·½·¨È¥¹©Óû§»ñµÃÏ̳߳ص±Ç°µÄÔËÐÐ״̬¡¢Ï̸߳öÊý¡£ÕâÀﶼʹÓõÄÊÇλÔËËãµÄ·½Ê½,Ïà±ÈÓÚ»ù±¾ÔËËã,ËÙ¶ÈÒ²»á¿ìºÜ¶à¡£
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3.3 Ï̳߳ØÈçºÎ¹ÜÀíÈÎÎñ
3.3.1 ÈÎÎñµ÷¶È
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threadPool.execute(new Job());
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3.3.3 ÈÎÎñÉêÇë
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3.3.4 ÈÎÎñ¾Ü¾ø
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3.4 Ï̳߳ØÈçºÎ¹ÜÀíÏß³Ì
3.4.1 WorkerÏß³Ì
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firstTask ÓÃËüÀ´±£´æ´«ÈëµÄµÚÒ»¸öÈÎÎñ,Õâ¸öÈÎÎñ¿ÉÒÔÓÐÒ²¿ÉÒÔΪ null¡£Èç¹ûÕâ¸öÖµÊÇ·Ç¿ÕµÄ,ÄÇôÏ߳̾ͻáÔÚÆô¶¯³õÆÚÁ¢¼´Ö´ÐÐÕâ¸öÈÎÎñ,Ò²¾Í¶ÔÓ¦ºËÐÄÏ̴߳´½¨Ê±µÄÇé¿ö;Èç¹ûÕâ¸öÖµÊÇ¿ÕµÄ,ÄÇô¾ÍÐèÒª´´½¨Ò»¸öÏß³ÌÈ¥Ö´ÐÐÈÎÎñÁбí(workQueue)ÖеÄÈÎÎñ,Ò²¾ÍÊǷǺËÐÄÏ̵߳Ĵ´½¨¡£
3.4.1.1 AQS ×÷ÓÃ
Worker ¼Ì³ÐÁË AbstractQueuedSynchronizer,Ö÷ҪĿµÄÓÐÁ½¸ö:
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3.4.1.2 Runnable ×÷ÓÃ
Worker »¹ÊµÏÖÁË Runnable,ËüÓÐÁ½¸öÊôÐÔ thead¡¢firstTask¡£
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Worker Ö´ÐÐÈÎÎñµÄÄ£ÐÍÈçÏÂͼËùʾ:
3.4.2 Worker Ïß³ÌÔö¼Ó
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3.4.3 Worker Ïß³ÌÖ´ÐÐÈÎÎñ
Worker ÖеÄÏß³Ì start µÄʱºò,µ÷Óà Worker ±¾Éí run ·½·¨,Õâ¸ö run ·½·¨µ÷ÓÃÍⲿÀàThreadPoolExecutor µÄ runWorker ·½·¨,Ö±½Ó¿´ runWorker ·½·¨µÄÔ´Âë:
Ö´ÐÐÁ÷³ÌÈçÏÂ:
3.4.4 Worker Ï̻߳ØÊÕ
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3.4.4 Worker Ï̹߳رÕ
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3.4.4.1 shutdown
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3.4.4.2 shutdownNow
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3.4.4.3 Worker Ï̹߳رÕС½á
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