{"id":37285,"date":"2023-12-11T14:40:52","date_gmt":"2023-12-11T06:40:52","guid":{"rendered":"https:\/\/wx.kaifamiao.info\/?p=37285"},"modified":"2023-12-11T14:40:52","modified_gmt":"2023-12-11T06:40:52","slug":"aqs%e5%ba%95%e5%b1%82%e4%bd%bf%e7%94%a8%e4%ba%86%e6%a8%a1%e6%9d%bf%e6%96%b9%e6%b3%95%e6%a8%a1%e5%bc%8f%ef%bc%9f","status":"publish","type":"post","link":"http:\/\/wx.kaifamiao.info\/index.php\/2023\/12\/11\/aqs%e5%ba%95%e5%b1%82%e4%bd%bf%e7%94%a8%e4%ba%86%e6%a8%a1%e6%9d%bf%e6%96%b9%e6%b3%95%e6%a8%a1%e5%bc%8f%ef%bc%9f\/","title":{"rendered":"AQS\u5e95\u5c42\u4f7f\u7528\u4e86\u6a21\u677f\u65b9\u6cd5\u6a21\u5f0f\uff1f"},"content":{"rendered":"

“`\u540c\u6b65\u5668\u7684\u8bbe\u8ba1\u662f\u57fa\u4e8e\u6a21\u677f\u65b9\u6cd5\u6a21\u5f0f\u7684\uff0c\u5982\u679c\u9700\u8981\u81ea\u5b9a\u4e49\u540c\u6b65\u5668\u4e00\u822c\u7684\u65b9\u5f0f\u662f\u8fd9\u6837\uff08\u6a21\u677f\u65b9\u6cd5\u6a21\u5f0f\u5f88\u7ecf\u5178\u7684\u4e00\u4e2a\u5e94\u7528\uff09\uff1a<\/p>\n

    \n
  1. \u4f7f\u7528\u8005\u7ee7\u627fAbstractQueuedSynchronizer\u5e76\u91cd\u5199\u6307\u5b9a\u7684\u65b9\u6cd5\u3002\uff08\u8fd9\u4e9b\u91cd\u5199\u65b9\u6cd5\u5f88\u7b80\u5355\uff0c\u65e0\u975e\u662f\u5bf9\u4e8e\u5171\u4eab\u8d44\u6e90state\u7684\u83b7\u53d6\u548c\u91ca\u653e\uff09<\/li>\n
  2. \u5c06AQS\u7ec4\u5408\u5728\u81ea\u5b9a\u4e49\u540c\u6b65\u7ec4\u4ef6\u7684\u5b9e\u73b0\u4e2d\uff0c\u5e76\u8c03\u7528\u5176\u6a21\u677f\u65b9\u6cd5\uff0c\u800c\u8fd9\u4e9b\u6a21\u677f\u65b9\u6cd5\u4f1a\u8c03\u7528\u4f7f\u7528\u8005\u91cd\u5199\u7684\u65b9\u6cd5\u3002<\/li>\n<\/ol>\n

    \u8fd9\u548c\u6211\u4eec\u4ee5\u5f80\u901a\u8fc7\u5b9e\u73b0\u63a5\u53e3\u7684\u65b9\u5f0f\u6709\u5f88\u5927\u533a\u522b\uff0c\u8fd9\u662f\u6a21\u677f\u65b9\u6cd5\u6a21\u5f0f\u5f88\u7ecf\u5178\u7684\u4e00\u4e2a\u8fd0\u7528\uff0c\u4e0b\u9762\u7b80\u5355\u7684\u7ed9\u5927\u5bb6\u4ecb\u7ecd\u4e00\u4e0b\u6a21\u677f\u65b9\u6cd5\u6a21\u5f0f\uff0c\u6a21\u677f\u65b9\u6cd5\u6a21\u5f0f\u662f\u4e00\u4e2a\u5f88\u5bb9\u6613\u7406\u89e3\u7684\u8bbe\u8ba1\u6a21\u5f0f\u4e4b\u4e00\u3002<\/p>\n

    \u6a21\u677f\u65b9\u6cd5\u6a21\u5f0f\u662f\u57fa\u4e8e\u201d\u7ee7\u627f\u201c\u7684\uff0c\u4e3b\u8981\u662f\u4e3a\u4e86\u5728\u4e0d\u6539\u53d8\u6a21\u677f\u7ed3\u6784\u7684\u524d\u63d0\u4e0b\u5728\u5b50\u7c7b\u4e2d\u91cd\u65b0\u5b9a\u4e49\u6a21\u677f\u4e2d\u7684\u5185\u5bb9\u4ee5\u5b9e\u73b0\u590d\u7528\u4ee3\u7801\u3002\u4e3e\u4e2a\u5f88\u7b80\u5355\u7684\u4f8b\u5b50\u5047\u5982\u6211\u4eec\u8981\u53bb\u4e00\u4e2a\u5730\u65b9\u7684\u6b65\u9aa4\u662f\uff1a\u8d2d\u7968buyTicket()<\/code>->\u5b89\u68c0securityCheck()<\/code>->\u4e58\u5750\u67d0\u67d0\u5de5\u5177\u56de\u5bb6ride()<\/code>->\u5230\u8fbe\u76ee\u7684\u5730arrive()<\/code>\u3002\u6211\u4eec\u53ef\u80fd\u4e58\u5750\u4e0d\u540c\u7684\u4ea4\u901a\u5de5\u5177\u56de\u5bb6\u6bd4\u5982\u98de\u673a\u6216\u8005\u706b\u8f66\uff0c\u6240\u4ee5\u9664\u4e86ride()<\/code>\u65b9\u6cd5\uff0c\u5176\u4ed6\u65b9\u6cd5\u7684\u5b9e\u73b0\u51e0\u4e4e\u76f8\u540c\u3002\u6211\u4eec\u53ef\u4ee5\u5b9a\u4e49\u4e00\u4e2a\u5305\u542b\u4e86\u8fd9\u4e9b\u65b9\u6cd5\u7684\u62bd\u8c61\u7c7b\uff0c\u7136\u540e\u7528\u6237\u6839\u636e\u81ea\u5df1\u7684\u9700\u8981\u7ee7\u627f\u8be5\u62bd\u8c61\u7c7b\u7136\u540e\u4fee\u6539 ride()<\/code>\u65b9\u6cd5\u3002<\/p>\n<\/blockquote>\n

    AQS\u4f7f\u7528\u4e86\u6a21\u677f\u65b9\u6cd5\u6a21\u5f0f\uff0c\u81ea\u5b9a\u4e49\u540c\u6b65\u5668\u65f6\u9700\u8981\u91cd\u5199\u4e0b\u9762\u51e0\u4e2aAQS\u63d0\u4f9b\u7684\u6a21\u677f\u65b9\u6cd5\uff1a<\/strong><\/p>\n

    <\/code>`javaisHeldExclusively()\/\/\u8be5\u7ebf\u7a0b\u662f\u5426\u6b63\u5728\u72ec\u5360\u8d44\u6e90\u3002\u53ea\u6709\u7528\u5230condition\u624d\u9700\u8981\u53bb\u5b9e\u73b0\u5b83\u3002tryAcquire(int)\/\/\u72ec\u5360\u65b9\u5f0f\u3002\u5c1d\u8bd5\u83b7\u53d6\u8d44\u6e90\uff0c\u6210\u529f\u5219\u8fd4\u56detrue\uff0c\u5931\u8d25\u5219\u8fd4\u56defalse\u3002tryRelease(int)\/\/\u72ec\u5360\u65b9\u5f0f\u3002\u5c1d\u8bd5\u91ca\u653e\u8d44\u6e90\uff0c\u6210\u529f\u5219\u8fd4\u56detrue\uff0c\u5931\u8d25\u5219\u8fd4\u56defalse\u3002tryAcquireShared(int)\/\/\u5171\u4eab\u65b9\u5f0f\u3002\u5c1d\u8bd5\u83b7\u53d6\u8d44\u6e90\u3002\u8d1f\u6570\u8868\u793a\u5931\u8d25\uff1b0\u8868\u793a\u6210\u529f\uff0c\u4f46\u6ca1\u6709\u5269\u4f59\u53ef\u7528\u8d44\u6e90\uff1b\u6b63\u6570\u8868\u793a\u6210\u529f\uff0c\u4e14\u6709\u5269\u4f59\u8d44\u6e90\u3002tryReleaseShared(int)\/\/\u5171\u4eab\u65b9\u5f0f\u3002\u5c1d\u8bd5\u91ca\u653e\u8d44\u6e90\uff0c\u6210\u529f\u5219\u8fd4\u56detrue\uff0c\u5931\u8d25\u5219\u8fd4\u56defalse\u3002<\/p>\n

    <\/code>`<\/p>\n

    \u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0c\u6bcf\u4e2a\u65b9\u6cd5\u90fd\u629b\u51fa UnsupportedOperationException<\/code>\u3002 \u8fd9\u4e9b\u65b9\u6cd5\u7684\u5b9e\u73b0\u5fc5\u987b\u662f\u5185\u90e8\u7ebf\u7a0b\u5b89\u5168\u7684\uff0c\u5e76\u4e14\u901a\u5e38\u5e94\u8be5\u7b80\u77ed\u800c\u4e0d\u662f\u963b\u585e\u3002AQS\u7c7b\u4e2d\u7684\u5176\u4ed6\u65b9\u6cd5\u90fd\u662ffinal \uff0c\u6240\u4ee5\u65e0\u6cd5\u88ab\u5176\u4ed6\u7c7b\u4f7f\u7528\uff0c\u53ea\u6709\u8fd9\u51e0\u4e2a\u65b9\u6cd5\u53ef\u4ee5\u88ab\u5176\u4ed6\u7c7b\u4f7f\u7528\u3002<\/p>\n

    \u4ee5ReentrantLock\u4e3a\u4f8b\uff0cstate\u521d\u59cb\u5316\u4e3a0\uff0c\u8868\u793a\u672a\u9501\u5b9a\u72b6\u6001\u3002A\u7ebf\u7a0block()\u65f6\uff0c\u4f1a\u8c03\u7528tryAcquire()\u72ec\u5360\u8be5\u9501\u5e76\u5c06state+1\u3002\u6b64\u540e\uff0c\u5176\u4ed6\u7ebf\u7a0b\u518dtryAcquire()\u65f6\u5c31\u4f1a\u5931\u8d25\uff0c\u76f4\u5230A\u7ebf\u7a0bunlock()\u5230state=0\uff08\u5373\u91ca\u653e\u9501\uff09\u4e3a\u6b62\uff0c\u5176\u5b83\u7ebf\u7a0b\u624d\u6709\u673a\u4f1a\u83b7\u53d6\u8be5\u9501\u3002\u5f53\u7136\uff0c\u91ca\u653e\u9501\u4e4b\u524d\uff0cA\u7ebf\u7a0b\u81ea\u5df1\u662f\u53ef\u4ee5\u91cd\u590d\u83b7\u53d6\u6b64\u9501\u7684\uff08state\u4f1a\u7d2f\u52a0\uff09\uff0c\u8fd9\u5c31\u662f\u53ef\u91cd\u5165\u7684\u6982\u5ff5\u3002\u4f46\u8981\u6ce8\u610f\uff0c\u83b7\u53d6\u591a\u5c11\u6b21\u5c31\u8981\u91ca\u653e\u591a\u4e48\u6b21\uff0c\u8fd9\u6837\u624d\u80fd\u4fdd\u8bc1state\u662f\u80fd\u56de\u5230\u96f6\u6001\u7684\u3002<\/p>\n

    \u518d\u4ee5CountDownLatch\u4ee5\u4f8b\uff0c\u4efb\u52a1\u5206\u4e3aN\u4e2a\u5b50\u7ebf\u7a0b\u53bb\u6267\u884c\uff0cstate\u4e5f\u521d\u59cb\u5316\u4e3aN\uff08\u6ce8\u610fN\u8981\u4e0e\u7ebf\u7a0b\u4e2a\u6570\u4e00\u81f4\uff09\u3002\u8fd9N\u4e2a\u5b50\u7ebf\u7a0b\u662f\u5e76\u884c\u6267\u884c\u7684\uff0c\u6bcf\u4e2a\u5b50\u7ebf\u7a0b\u6267\u884c\u5b8c\u540ecountDown()\u4e00\u6b21\uff0cstate\u4f1aCAS(Compare and Swap)\u51cf1\u3002\u7b49\u5230\u6240\u6709\u5b50\u7ebf\u7a0b\u90fd\u6267\u884c\u5b8c\u540e(\u5373state=0)\uff0c\u4f1aunpark()\u4e3b\u8c03\u7528\u7ebf\u7a0b\uff0c\u7136\u540e\u4e3b\u8c03\u7528\u7ebf\u7a0b\u5c31\u4f1a\u4eceawait()\u51fd\u6570\u8fd4\u56de\uff0c\u7ee7\u7eed\u540e\u4f59\u52a8\u4f5c\u3002<\/p>\n

    \u4e00\u822c\u6765\u8bf4\uff0c\u81ea\u5b9a\u4e49\u540c\u6b65\u5668\u8981\u4e48\u662f\u72ec\u5360\u65b9\u6cd5\uff0c\u8981\u4e48\u662f\u5171\u4eab\u65b9\u5f0f\uff0c\u4ed6\u4eec\u4e5f\u53ea\u9700\u5b9e\u73b0tryAcquire-tryRelease<\/code>\u3001tryAcquireShared-tryReleaseShared<\/code>\u4e2d\u7684\u4e00\u79cd\u5373\u53ef\u3002\u4f46AQS\u4e5f\u652f\u6301\u81ea\u5b9a\u4e49\u540c\u6b65\u5668\u540c\u65f6\u5b9e\u73b0\u72ec\u5360\u548c\u5171\u4eab\u4e24\u79cd\u65b9\u5f0f\uff0c\u5982ReentrantReadWriteLock<\/code>\u3002<\/p>\n

    “`<\/p>\n","protected":false},"excerpt":{"rendered":"

    “`\u540c\u6b65\u5668\u7684\u8bbe\u8ba1\u662f\u57fa\u4e8e\u6a21\u677f\u65b9\u6cd5\u6a21\u5f0f\u7684\uff0c\u5982\u679c\u9700\u8981\u81ea\u5b9a\u4e49\u540c\u6b65\u5668\u4e00\u822c\u7684\u65b9\u5f0f\u662f\u8fd9\u6837\uff08\u6a21\u677f\u65b9\u6cd5\u6a21\u5f0f\u5f88\u7ecf\u5178\u7684\u4e00 […]<\/p>\n","protected":false},"author":7,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-37285","post","type-post","status-publish","format-standard","hentry","category-c"],"_links":{"self":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/37285","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/comments?post=37285"}],"version-history":[{"count":1,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/37285\/revisions"}],"predecessor-version":[{"id":37286,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/37285\/revisions\/37286"}],"wp:attachment":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/media?parent=37285"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/categories?post=37285"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/tags?post=37285"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}