{"id":792,"date":"2014-02-14T21:22:56","date_gmt":"2014-02-14T13:22:56","guid":{"rendered":"http:\/\/coderbee.net\/?p=792"},"modified":"2014-02-26T08:56:10","modified_gmt":"2014-02-26T00:56:10","slug":"juc-%e5%8f%af%e9%87%8d%e5%85%a5-%e8%af%bb%e5%86%99%e9%94%81-reentrantreadwritelock","status":"publish","type":"post","link":"https:\/\/coderbee.net\/index.php\/concurrent\/20140214\/792","title":{"rendered":"JUC \u53ef\u91cd\u5165 \u8bfb\u5199\u9501 ReentrantReadWriteLock"},"content":{"rendered":"<h2>\u8bfb\u5199\u9501 ReadWriteLock<\/h2>\n<p>\u8bfb\u5199\u9501\u7ef4\u62a4\u4e86\u4e00\u5bf9\u76f8\u5173\u7684\u9501\uff0c\u4e00\u4e2a\u7528\u4e8e\u53ea\u8bfb\u64cd\u4f5c\uff0c\u4e00\u4e2a\u7528\u4e8e\u5199\u5165\u64cd\u4f5c\u3002\u53ea\u8981\u6ca1\u6709writer\uff0c\u8bfb\u53d6\u9501\u53ef\u4ee5\u7531\u591a\u4e2areader\u7ebf\u7a0b\u540c\u65f6\u4fdd\u6301\u3002\u5199\u5165\u9501\u662f\u72ec\u5360\u7684\u3002<\/p>\n<p>\u4e92\u65a5\u9501\u4e00\u6b21\u53ea\u5141\u8bb8\u4e00\u4e2a\u7ebf\u7a0b\u8bbf\u95ee\u5171\u4eab\u6570\u636e\uff0c\u54ea\u6015\u8fdb\u884c\u7684\u662f\u53ea\u8bfb\u64cd\u4f5c\uff1b\u8bfb\u5199\u9501\u5141\u8bb8\u5bf9\u5171\u4eab\u6570\u636e\u8fdb\u884c\u66f4\u9ad8\u7ea7\u522b\u7684\u5e76\u53d1\u8bbf\u95ee\uff1a\u5bf9\u4e8e\u5199\u64cd\u4f5c\uff0c\u4e00\u6b21\u53ea\u6709\u4e00\u4e2a\u7ebf\u7a0b\uff08write\u7ebf\u7a0b\uff09\u53ef\u4ee5\u4fee\u6539\u5171\u4eab\u6570\u636e\uff0c\u5bf9\u4e8e\u8bfb\u64cd\u4f5c\uff0c\u5141\u8bb8\u4efb\u610f\u6570\u91cf\u7684\u7ebf\u7a0b\u540c\u65f6\u8fdb\u884c\u8bfb\u53d6\u3002<\/p>\n<p>\u4e0e\u4e92\u65a5\u9501\u76f8\u6bd4\uff0c\u4f7f\u7528\u8bfb\u5199\u9501\u80fd\u5426\u63d0\u5347\u6027\u80fd\u5219\u53d6\u51b3\u4e8e\u8bfb\u5199\u64cd\u4f5c\u671f\u95f4\u8bfb\u53d6\u6570\u636e\u76f8\u5bf9\u4e8e\u4fee\u6539\u6570\u636e\u7684\u9891\u7387\uff0c\u4ee5\u53ca\u6570\u636e\u7684\u4e89\u7528\u2014\u2014\u5373\u5728\u540c\u4e00\u65f6\u95f4\u8bd5\u56fe\u5bf9\u8be5\u6570\u636e\u6267\u884c\u8bfb\u53d6\u6216\u5199\u5165\u64cd\u4f5c\u7684\u7ebf\u7a0b\u6570\u3002<\/p>\n<p>\u8bfb\u5199\u9501\u9002\u7528\u4e8e\u8bfb\u591a\u5199\u5c11\u7684\u60c5\u51b5\u3002<\/p>\n<h2>\u53ef\u91cd\u5165\u8bfb\u5199\u9501 ReentrantReadWriteLock<\/h2>\n<h3>\u5c5e\u6027<\/h3>\n<p><code>ReentrantReadWriteLock<\/code> \u4e5f\u662f\u57fa\u4e8e <code>AbstractQueuedSynchronizer<\/code> \u5b9e\u73b0\u7684\uff0c\u5b83\u5177\u6709\u4e0b\u9762\u8fd9\u4e9b\u5c5e\u6027\uff08\u6765\u81eaJava doc\u6587\u6863\uff09\uff1a<\/p>\n<ul>\n<li>\u83b7\u53d6\u987a\u5e8f\uff1a\u6b64\u7c7b\u4e0d\u4f1a\u5c06\u8bfb\u53d6\u8005\u4f18\u5148\u6216\u5199\u5165\u8005\u4f18\u5148\u5f3a\u52a0\u7ed9\u9501\u8bbf\u95ee\u7684\u6392\u5e8f\u3002<br \/>\n<blockquote>\n<ul>\n<li>\u975e\u516c\u5e73\u6a21\u5f0f\uff08\u9ed8\u8ba4\uff09\uff1a\u8fde\u7eed\u7ade\u4e89\u7684\u975e\u516c\u5e73\u9501\u53ef\u80fd\u65e0\u9650\u671f\u5730\u63a8\u8fdf\u4e00\u4e2a\u6216\u591a\u4e2areader\u6216writer\u7ebf\u7a0b\uff0c\u4f46\u541e\u5410\u91cf\u901a\u5e38\u8981\u9ad8\u4e8e\u516c\u5e73\u9501\u3002<\/li>\n<li>\u516c\u5e73\u6a21\u5f0f\uff1a\u7ebf\u7a0b\u5229\u7528\u4e00\u4e2a\u8fd1\u4f3c\u5230\u8fbe\u987a\u5e8f\u7684\u7b56\u7565\u6765\u4e89\u593a\u8fdb\u5165\u3002\u5f53\u91ca\u653e\u5f53\u524d\u4fdd\u6301\u7684\u9501\u65f6\uff0c\u53ef\u4ee5\u4e3a\u7b49\u5f85\u65f6\u95f4\u6700\u957f\u7684\u5355\u4e2awriter\u7ebf\u7a0b\u5206\u914d\u5199\u5165\u9501\uff0c\u5982\u679c\u6709\u4e00\u7ec4\u7b49\u5f85\u65f6\u95f4\u5927\u4e8e\u6240\u6709\u6b63\u5728\u7b49\u5f85\u7684writer\u7ebf\u7a0b\u7684reader\uff0c\u5c06\u4e3a\u8be5\u7ec4\u5206\u914d\u8bfb\u8005\u9501\u3002<\/li>\n<li>\u8bd5\u56fe\u83b7\u5f97\u516c\u5e73\u5199\u5165\u9501\u7684\u975e\u91cd\u5165\u7684\u7ebf\u7a0b\u5c06\u4f1a\u963b\u585e\uff0c\u9664\u975e\u8bfb\u53d6\u9501\u548c\u5199\u5165\u9501\u90fd\u81ea\u7531\uff08\u8fd9\u610f\u5473\u7740\u6ca1\u6709\u7b49\u5f85\u7ebf\u7a0b\uff09\u3002<\/li>\n<\/ul>\n<\/blockquote>\n<\/li>\n<li>\u91cd\u5165\uff1a\u6b64\u9501\u5141\u8bb8reader\u548cwriter\u6309\u7167 <code>ReentrantLock<\/code> \u7684\u6837\u5f0f\u91cd\u65b0\u83b7\u53d6\u8bfb\u53d6\u9501\u6216\u5199\u5165\u9501\u3002\u5728\u5199\u5165\u7ebf\u7a0b\u4fdd\u6301\u7684\u6240\u6709\u5199\u5165\u9501\u90fd\u5df2\u7ecf\u91ca\u653e\u540e\uff0c\u624d\u5141\u8bb8\u91cd\u5165reader\u4f7f\u7528\u8bfb\u53d6\u9501\u3002<br \/>\nwriter\u53ef\u4ee5\u83b7\u53d6\u8bfb\u53d6\u9501\uff0c\u4f46reader\u4e0d\u80fd\u83b7\u53d6\u5199\u5165\u9501\u3002<\/p>\n<\/li>\n<li>\n<p>\u9501\u964d\u7ea7\uff1a\u91cd\u5165\u8fd8\u5141\u8bb8\u4ece\u5199\u5165\u9501\u964d\u7ea7\u4e3a\u8bfb\u53d6\u9501\uff0c\u5b9e\u73b0\u65b9\u5f0f\u662f\uff1a\u5148\u83b7\u53d6\u5199\u5165\u9501\uff0c\u7136\u540e\u83b7\u53d6\u8bfb\u53d6\u9501\uff0c\u6700\u540e\u91ca\u653e\u5199\u5165\u9501\u3002\u4f46\u662f\uff0c<strong>\u4ece\u8bfb\u53d6\u9501\u5347\u7ea7\u5230\u5199\u5165\u9501\u662f\u4e0d\u53ef\u80fd\u7684\u3002<\/strong><\/p>\n<\/li>\n<li>\n<p>\u9501\u83b7\u53d6\u7684\u4e2d\u65ad\uff1a\u8bfb\u53d6\u9501\u548c\u5199\u5165\u9501\u90fd\u652f\u6301\u9501\u83b7\u53d6\u671f\u95f4\u7684\u4e2d\u65ad\u3002<\/p>\n<\/li>\n<li>\n<p>Condition \u652f\u6301\uff1a\u5199\u5165\u9501\u63d0\u4f9b\u4e86\u4e00\u4e2a <code>Condition<\/code> \u5b9e\u73b0\uff0c\u5bf9\u4e8e\u5199\u5165\u9501\u6765\u8bf4\uff0c\u8be5\u5b9e\u73b0\u7684\u884c\u4e3a\u4e0e <code>ReentrantLock.newCondition()<\/code> \u63d0\u4f9b\u7684 <code>Condition<\/code> \u5b9e\u73b0\u5bf9 <code>ReentrantLock<\/code> \u6240\u505a\u7684\u884c\u4e3a\u76f8\u540c\u3002\u5f53\u7136\uff0c\u6b64 <code>Condition<\/code> \u53ea\u80fd\u7528\u4e8e\u5199\u5165\u9501\u3002<br \/>\n\u8bfb\u53d6\u9501\u4e0d\u652f\u6301 <code>Condition<\/code>\uff0c<code>readLock().newCondition()<\/code> \u4f1a\u629b\u51fa <code>UnsupportedOperationException<\/code>\u3002<\/p>\n<\/li>\n<li>\n<p>\u76d1\u6d4b\uff1a\u6b64\u7c7b\u652f\u6301\u4e00\u4e9b\u786e\u5b9a\u662f\u8bfb\u53d6\u9501\u8fd8\u662f\u5199\u5165\u9501\u7684\u65b9\u6cd5\u3002\u8fd9\u4e9b\u65b9\u6cd5\u8bbe\u8ba1\u7528\u4e8e\u76d1\u89c6\u7cfb\u7edf\u72b6\u6001\uff0c\u800c\u4e0d\u662f\u540c\u6b65\u63a7\u5236\u3002<\/p>\n<\/li>\n<\/ul>\n<p><!--more--><\/p>\n<h3>\u5b9e\u73b0<\/h3>\n<h4>AQS \u56de\u987e<\/h4>\n<p>\u5728\u4e4b\u524d\u7684\u6587\u7ae0\u5df2\u7ecf\u63d0\u5230\uff0cAQS\u4ee5\u5355\u4e2a <code>int<\/code> \u7c7b\u578b\u7684\u539f\u5b50\u53d8\u91cf\u6765\u8868\u793a\u5176\u72b6\u6001\uff0c\u5b9a\u4e49\u4e864\u4e2a\u62bd\u8c61\u65b9\u6cd5\uff08 <code>tryAcquire(int)\u3001tryRelease(int)\u3001tryAcquireShared(int)\u3001tryReleaseShared(int)<\/code>\uff0c\u524d\u4e24\u4e2a\u65b9\u6cd5\u7528\u4e8e\u72ec\u5360\/\u6392\u4ed6\u6a21\u5f0f\uff0c\u540e\u4e24\u4e2a\u7528\u4e8e\u5171\u4eab\u6a21\u5f0f \uff09\u7559\u7ed9\u5b50\u7c7b\u5b9e\u73b0\uff0c\u7528\u4e8e\u81ea\u5b9a\u4e49\u540c\u6b65\u5668\u7684\u884c\u4e3a\u4ee5\u5b9e\u73b0\u7279\u5b9a\u7684\u529f\u80fd\u3002<\/p>\n<p>\u5bf9\u4e8e <code>ReentrantLock<\/code>\uff0c\u5b83\u662f\u53ef\u91cd\u5165\u7684\u72ec\u5360\u9501\uff0c\u5185\u90e8\u7684 <code>Sync<\/code> \u7c7b\u5b9e\u73b0\u4e86 <code>tryAcquire(int)\u3001tryRelease(int)<\/code> \u65b9\u6cd5\uff0c\u5e76\u7528\u72b6\u6001\u7684\u503c\u6765\u8868\u793a\u91cd\u5165\u6b21\u6570\uff0c\u52a0\u9501\u6216\u91cd\u5165\u9501\u65f6\u72b6\u6001\u52a0 1\uff0c\u91ca\u653e\u9501\u65f6\u72b6\u6001\u51cf 1\uff0c\u72b6\u6001\u503c\u7b49\u4e8e 0 \u8868\u793a\u9501\u7a7a\u95f2\u3002<\/p>\n<p>\u5bf9\u4e8e <code>CountDownLatch<\/code>\uff0c\u5b83\u662f\u4e00\u4e2a\u5173\u5361\uff0c\u5728\u6761\u4ef6\u6ee1\u8db3\u524d\u963b\u585e\u6240\u6709\u7b49\u5f85\u7ebf\u7a0b\uff0c\u6761\u4ef6\u6ee1\u8db3\u540e\u5141\u8bb8\u6240\u6709\u7ebf\u7a0b\u901a\u8fc7\u3002\u5185\u90e8\u7c7b <code>Sync<\/code> \u628a\u72b6\u6001\u521d\u59cb\u5316\u4e3a\u5927\u4e8e 0 \u7684\u67d0\u4e2a\u503c\uff0c\u5f53\u72b6\u6001\u5927\u4e8e 0 \u65f6\u6240\u6709wait\u7ebf\u7a0b\u963b\u585e\uff0c\u6bcf\u8c03\u7528\u4e00\u6b21 countDown \u65b9\u6cd5\u5c31\u628a\u72b6\u6001\u503c\u51cf 1\uff0c\u51cf\u4e3a 0 \u65f6\u5141\u8bb8\u6240\u6709\u7ebf\u7a0b\u901a\u8fc7\u3002\u5229\u7528\u4e86AQS\u7684\u5171\u4eab\u6a21\u5f0f\u3002<\/p>\n<p>\u73b0\u5728\uff0c\u8981\u7528AQS\u6765\u5b9e\u73b0 <code>ReentrantReadWriteLock<\/code>\u3002<\/p>\n<h4>\u4e00\u70b9\u601d\u8003\u95ee\u9898<\/h4>\n<ul>\n<li>AQS\u53ea\u6709\u4e00\u4e2a\u72b6\u6001\uff0c\u90a3\u4e48\u5982\u4f55\u8868\u793a \u591a\u4e2a\u8bfb\u9501 \u4e0e \u5355\u4e2a\u5199\u9501 \u5462\uff1f<\/li>\n<li><code>ReentrantLock<\/code> \u91cc\uff0c\u72b6\u6001\u503c\u8868\u793a\u91cd\u5165\u8ba1\u6570\uff0c\u73b0\u5728\u5982\u4f55\u5728AQS\u91cc\u8868\u793a\u6bcf\u4e2a\u8bfb\u9501\u3001\u5199\u9501\u7684\u91cd\u5165\u6b21\u6570\u5462\uff1f<\/li>\n<li>\u5982\u4f55\u5b9e\u73b0\u8bfb\u9501\u3001\u5199\u9501\u7684\u516c\u5e73\u6027\u5462\uff1f<\/li>\n<\/ul>\n<h4>\u4e00\u70b9\u63d0\u793a<\/h4>\n<ul>\n<li>\u4e00\u4e2a\u72b6\u6001\u662f\u6ca1\u6cd5\u65e2\u8868\u793a\u8bfb\u9501\uff0c\u53c8\u8868\u793a\u5199\u9501\u7684\uff0c\u4e0d\u591f\u7528\u554a\uff0c\u90a3\u5c31\u8fa6\u6210\u4e24\u4efd\u7528\u4e86\uff0c\u5ba2\u5bb6\u8bdd\u8bf4\u4e00\u4e2a\u996d\u7c92\u54ac\u6210\u4e24\u534a\u5403\uff0c\u72b6\u6001\u7684\u9ad8\u4f4d\u90e8\u5206\u8868\u793a\u8bfb\u9501\uff0c\u4f4e\u4f4d\u8868\u793a\u5199\u9501\uff0c\u7531\u4e8e\u5199\u9501\u53ea\u6709\u4e00\u4e2a\uff0c\u6240\u4ee5\u5199\u9501\u7684\u91cd\u5165\u8ba1\u6570\u4e5f\u89e3\u51b3\u4e86\uff0c\u8fd9\u4e5f\u4f1a\u5bfc\u81f4\u5199\u9501\u53ef\u91cd\u5165\u7684\u6b21\u6570\u51cf\u5c0f\u3002<\/li>\n<li>\u7531\u4e8e\u8bfb\u9501\u53ef\u4ee5\u540c\u65f6\u6709\u591a\u4e2a\uff0c\u80af\u5b9a\u4e0d\u80fd\u518d\u7528\u8fa6\u6210\u4e24\u4efd\u7528\u7684\u65b9\u6cd5\u6765\u5904\u7406\u4e86\uff0c\u4f46\u6211\u4eec\u6709 <code>ThreadLocal<\/code>\uff0c\u53ef\u4ee5\u628a\u7ebf\u7a0b\u91cd\u5165\u8bfb\u9501\u7684\u6b21\u6570\u4f5c\u4e3a\u503c\u5b58\u5728 <code>ThreadLocal<\/code> \u91cc\u3002<\/li>\n<li>\u5bf9\u4e8e\u516c\u5e73\u6027\u7684\u5b9e\u73b0\uff0c\u53ef\u4ee5\u901a\u8fc7AQS\u7684\u7b49\u5f85\u961f\u5217\u548c\u5b83\u7684\u62bd\u8c61\u65b9\u6cd5\u6765\u63a7\u5236\uff0c\u5728\u72b6\u6001\u503c\u7684\u53e6\u4e00\u534a\u91cc\u5b58\u50a8\u5f53\u524d\u6301\u6709\u8bfb\u9501\u7684\u7ebf\u7a0b\u6570\u3002\u5982\u679c\u8bfb\u7ebf\u7a0b\u7533\u8bf7\u8bfb\u9501\uff0c\u5f53\u524d\u5199\u9501\u91cd\u5165\u6b21\u6570\u4e0d\u4e3a 0 \u65f6\uff0c\u5219\u7b49\u5f85\uff0c\u5426\u5219\u53ef\u4ee5\u9a6c\u4e0a\u5206\u914d\uff1b\u5982\u679c\u662f\u5199\u7ebf\u7a0b\u7533\u8bf7\u5199\u9501\uff0c\u5f53\u524d\u72b6\u6001\u4e3a 0 \u5219\u53ef\u4ee5\u9a6c\u4e0a\u5206\u914d\uff0c\u5426\u5219\u7b49\u5f85\u3002<\/li>\n<\/ul>\n<h4>\u6e90\u7801\u5206\u6790<\/h4>\n<p>\u73b0\u5728\u6765\u770b\u770b\u5177\u4f53\u7684\u5b9e\u73b0\u6e90\u7801\u3002<\/p>\n<h5>\u8fa6\u6210\u4e24\u4efd<\/h5>\n<p>AQS \u7684\u72b6\u6001\u662f32\u4f4d\uff08<code>int<\/code> \u7c7b\u578b\uff09\u7684\uff0c\u8fa6\u6210\u4e24\u4efd\uff0c\u8bfb\u9501\u7528\u9ad816\u4f4d\uff0c\u8868\u793a\u6301\u6709\u8bfb\u9501\u7684\u7ebf\u7a0b\u6570\uff08sharedCount\uff09\uff0c\u5199\u9501\u4f4e16\u4f4d\uff0c\u8868\u793a\u5199\u9501\u7684\u91cd\u5165\u6b21\u6570\uff08exclusiveCount\uff09\u3002\u72b6\u6001\u503c\u4e3a 0 \u8868\u793a\u9501\u7a7a\u95f2\uff0csharedCount\u4e0d\u4e3a 0 \u8868\u793a\u5206\u914d\u4e86\u8bfb\u9501\uff0cexclusiveCount \u4e0d\u4e3a 0 \u8868\u793a\u5206\u914d\u4e86\u5199\u9501\uff0csharedCount\u548cexclusiveCount \u80af\u5b9a\u4e0d\u4f1a\u540c\u65f6\u4e0d\u4e3a 0\u3002<\/p>\n<pre><code class=\"java\">abstract static class Sync extends AbstractQueuedSynchronizer {\n\n    \/\/ \n     \/\/ \n       static final int SHARED_SHIFT   = 16;\n\n       \/\/ \u7531\u4e8e\u8bfb\u9501\u7528\u9ad8\u4f4d\u90e8\u5206\uff0c\u6240\u4ee5\u8bfb\u9501\u4e2a\u6570\u52a01\uff0c\u5176\u5b9e\u662f\u72b6\u6001\u503c\u52a0 2^16\n       static final int SHARED_UNIT    = (1 &lt;&lt; SHARED_SHIFT);\n\n       \/\/ \u5199\u9501\u7684\u53ef\u91cd\u5165\u7684\u6700\u5927\u6b21\u6570\u3001\u8bfb\u9501\u5141\u8bb8\u7684\u6700\u5927\u6570\u91cf\n       static final int MAX_COUNT      = (1 &lt;&lt; SHARED_SHIFT) - 1;\n\n       \/\/ \u5199\u9501\u7684\u63a9\u7801\uff0c\u7528\u4e8e\u72b6\u6001\u7684\u4f4e16\u4f4d\u6709\u6548\u503c\n       static final int EXCLUSIVE_MASK = (1 &lt;&lt; SHARED_SHIFT) - 1;\n\n       \/\/ \u8bfb\u9501\u8ba1\u6570\uff0c\u5f53\u524d\u6301\u6709\u8bfb\u9501\u7684\u7ebf\u7a0b\u6570\n    static int sharedCount(int c)    { return c &gt;&gt;&gt; SHARED_SHIFT; }\n\n    \/\/ \u5199\u9501\u7684\u8ba1\u6570\uff0c\u4e5f\u5c31\u662f\u5b83\u7684\u91cd\u5165\u6b21\u6570\n    static int exclusiveCount(int c) { return c &amp; EXCLUSIVE_MASK; }\n}\n<\/code><\/pre>\n<h5>\u8bfb\u9501\u91cd\u5165\u8ba1\u6570<\/h5>\n<pre><code class=\"java\">abstract static class Sync extends AbstractQueuedSynchronizer {\n    \/**\n     * \u6bcf\u4e2a\u7ebf\u7a0b\u7279\u5b9a\u7684 read \u6301\u6709\u8ba1\u6570\u3002\u5b58\u653e\u5728ThreadLocal\uff0c\u4e0d\u9700\u8981\u662f\u7ebf\u7a0b\u5b89\u5168\u7684\u3002\n     *\/\n    static final class HoldCounter {\n        int count = 0;\n\n        \/\/ \u4f7f\u7528id\u800c\u4e0d\u662f\u5f15\u7528\u662f\u4e3a\u4e86\u907f\u514d\u4fdd\u7559\u5783\u573e\u3002\u6ce8\u610f\u8fd9\u662f\u4e2a\u5e38\u91cf\u3002\n        final long tid = Thread.currentThread().getId();\n    }\n\n    \/**\n     * \u91c7\u7528\u7ee7\u627f\u662f\u4e3a\u4e86\u91cd\u5199 initialValue \u65b9\u6cd5\uff0c\u8fd9\u6837\u5c31\u4e0d\u7528\u8fdb\u884c\u8fd9\u6837\u7684\u5904\u7406\uff1a\n     * \u5982\u679cThreadLocal\u6ca1\u6709\u5f53\u524d\u7ebf\u7a0b\u7684\u8ba1\u6570\uff0c\u5219new\u4e00\u4e2a\uff0c\u518d\u653e\u8fdbThreadLocal\u91cc\u3002\n     * \u53ef\u4ee5\u76f4\u63a5\u8c03\u7528 get\u3002\n     * *\/\n    static final class ThreadLocalHoldCounter\n        extends ThreadLocal&lt;HoldCounter&gt; {\n        public HoldCounter initialValue() {\n            return new HoldCounter();\n        }\n    }\n\n    \/**\n     * \u4fdd\u5b58\u5f53\u524d\u7ebf\u7a0b\u91cd\u5165\u8bfb\u9501\u7684\u6b21\u6570\u7684\u5bb9\u5668\u3002\u5728\u8bfb\u9501\u91cd\u5165\u6b21\u6570\u4e3a 0 \u65f6\u79fb\u9664\u3002\n     *\/\n    private transient ThreadLocalHoldCounter readHolds;\n\n    \/**\n     * \u6700\u8fd1\u4e00\u4e2a\u6210\u529f\u83b7\u53d6\u8bfb\u9501\u7684\u7ebf\u7a0b\u7684\u8ba1\u6570\u3002\u8fd9\u7701\u5374\u4e86ThreadLocal\u67e5\u627e\uff0c\n     * \u901a\u5e38\u60c5\u51b5\u4e0b\uff0c\u4e0b\u4e00\u4e2a\u91ca\u653e\u7ebf\u7a0b\u662f\u6700\u540e\u4e00\u4e2a\u83b7\u53d6\u7ebf\u7a0b\u3002\u8fd9\u4e0d\u662f volatile \u7684\uff0c\n     * \u56e0\u4e3a\u5b83\u4ec5\u7528\u4e8e\u8bd5\u63a2\u7684\uff0c\u7ebf\u7a0b\u8fdb\u884c\u7f13\u5b58\u4e5f\u662f\u53ef\u4ee5\u7684\n     * \uff08\u56e0\u4e3a\u5224\u65ad\u662f\u5426\u662f\u5f53\u524d\u7ebf\u7a0b\u662f\u901a\u8fc7\u7ebf\u7a0bid\u6765\u6bd4\u8f83\u7684\uff09\u3002\n     *\/\n    private transient HoldCounter cachedHoldCounter;\n\n    \/**\n     * firstReader\u662f\u8fd9\u6837\u4e00\u4e2a\u7279\u6b8a\u7ebf\u7a0b\uff1a\u5b83\u662f\u6700\u540e\u4e00\u4e2a\u628a \u5171\u4eab\u8ba1\u6570 \u4ece 0 \u6539\u4e3a 1 \u7684\n     * \uff08\u5728\u9501\u7a7a\u95f2\u7684\u65f6\u5019\uff09\uff0c\u800c\u4e14\u4ece\u90a3\u4e4b\u540e\u8fd8\u6ca1\u6709\u91ca\u653e\u8bfb\u9501\u7684\u3002\u5982\u679c\u4e0d\u5b58\u5728\u5219\u4e3anull\u3002\n     * firstReaderHoldCount \u662f firstReader \u7684\u91cd\u5165\u8ba1\u6570\u3002\n     *\n     * firstReader \u4e0d\u80fd\u5bfc\u81f4\u4fdd\u7559\u5783\u573e\uff0c\u56e0\u6b64\u5728 tryReleaseShared \u91cc\u8bbe\u7f6e\u4e3anull\uff0c\n     * \u9664\u975e\u7ebf\u7a0b\u5f02\u5e38\u7ec8\u6b62\uff0c\u6ca1\u6709\u91ca\u653e\u8bfb\u9501\u3002\n     *\n     * \u4f5c\u7528\u662f\u5728\u8ddf\u8e2a\u65e0\u7ade\u4e89\u7684\u8bfb\u9501\u8ba1\u6570\u65f6\u975e\u5e38\u4fbf\u5b9c\u3002\n     *\n     * firstReader\u53ca\u5176\u8ba1\u6570firstReaderHoldCount\u662f\u4e0d\u4f1a\u653e\u5165 readHolds \u7684\u3002\n     *\/\n    private transient Thread firstReader = null;\n    private transient int firstReaderHoldCount;\n\n    Sync() {\n        readHolds = new ThreadLocalHoldCounter();\n        setState(getState()); \/\/ \u786e\u4fdd readHolds \u7684\u5185\u5b58\u53ef\u89c1\u6027\uff0c\u5229\u7528 volatile \u5199\u7684\u5185\u5b58\u8bed\u4e49\u3002\n    }\n}\n<\/code><\/pre>\n<h4>\u5199\u9501\u83b7\u53d6\u4e0e\u91ca\u653e<\/h4>\n<p>\u5199\u9501\u7684\u83b7\u53d6\u4e0e\u91ca\u653e\u901a\u8fc7 <code>tryAcquire<\/code> \u548c <code>tryRelease<\/code> \u65b9\u6cd5\u5b9e\u73b0\uff0c\u6e90\u7801\u6587\u4ef6\u91cc\u6709\u8fd9\u4e48\u4e00\u6bb5\u8bf4\u660e\uff1a<code>tryRelease<\/code> \u548c <code>tryAcquire<\/code> \u53ef\u80fd\u88ab <code>Conditions<\/code> \u8c03\u7528\u3002\u56e0\u6b64\u53ef\u80fd\u51fa\u73b0\u53c2\u6570\u91cc\u5305\u542b\u5728\u6761\u4ef6\u7b49\u5f85\u548c\u7528 <code>tryAcquire<\/code> \u91cd\u65b0\u83b7\u53d6\u5230\u9501\u7684\u671f\u95f4\u5185\u5df2\u7ecf\u91ca\u653e\u7684 \u8bfb\u548c\u5199 \u8ba1\u6570\u3002<\/p>\n<p>\u8fd9\u8bf4\u660e\u770b\u8d77\u6765\u50cf\u662f\u5728 <code>tryAcquire<\/code> \u91cc\u8bbe\u7f6e\u72b6\u6001\u65f6\u8981\u8003\u8651\u65b9\u6cd5\u53c2\u6570(<code>acquires<\/code>)\u7684\u9ad8\u4f4d\u90e8\u5206\uff0c\u5176\u5b9e\u662f\u4e0d\u9700\u8981\u7684\u3002\u7531\u4e8e\u5199\u9501\u662f\u72ec\u5360\u7684\uff0c<code>acquires<\/code> \u8868\u793a\u7684\u53ea\u80fd\u662f\u5199\u9501\u7684\u8ba1\u6570\uff0c\u5982\u679c\u5f53\u524d\u7ebf\u7a0b\u6210\u529f\u83b7\u53d6\u5199\u9501\uff0c\u53ea\u9700\u8981\u7b80\u5355\u5730\u628a\u5f53\u524d\u72b6\u6001\u52a0\u4e0a <code>acquires<\/code> \u7684\u503c\u5373\u53ef\uff0c<code>tryRelease<\/code> \u91cc\u76f4\u63a5\u51cf\u53bb\u5176\u53c2\u6570\u503c\u5373\u53ef\u3002<\/p>\n<pre><code class=\"java\">protected final boolean tryAcquire(int acquires) {\n    Thread current = Thread.currentThread();\n    int c = getState();\n    int w = exclusiveCount(c);\n    if (c != 0) { \/\/ \u72b6\u6001\u4e0d\u4e3a0\uff0c\u8868\u793a\u9501\u88ab\u5206\u914d\u51fa\u53bb\u4e86\u3002\n\n        \/\/ (Note: if c != 0 and w == 0 then shared count != 0)\n      \/\/ c != 0 and w == 0 \u8868\u793a\u5206\u914d\u4e86\u8bfb\u9501\n      \/\/ w != 0 &amp;&amp; current != getExclusiveOwnerThread() \u8868\u793a\u5176\u4ed6\u7ebf\u7a0b\u83b7\u53d6\u4e86\u5199\u9501\u3002\n        if (w == 0 || current != getExclusiveOwnerThread())\n            return false ;\n\n        \/\/ \u5199\u9501\u91cd\u5165\n        \/\/ \u68c0\u6d4b\u662f\u5426\u8d85\u8fc7\u6700\u5927\u91cd\u5165\u6b21\u6570\u3002\n        if (w + exclusiveCount(acquires) &gt; MAX_COUNT)\n            throw new Error(\"Maximum lock count exceeded\");\n\n        \/\/ \u66f4\u65b0\u5199\u9501\u91cd\u5165\u6b21\u6570\uff0c\u5199\u9501\u5728\u4f4e\u4f4d\uff0c\u76f4\u63a5\u52a0\u4e0a acquire \u5373\u53ef\u3002\n        \/\/ Reentrant acquire\n        setState(c + acquires);\n        return true ;\n    }\n\n    \/\/ writerShouldBlock \u7559\u7ed9\u5b50\u7c7b\u5b9e\u73b0\uff0c\u7528\u4e8e\u5b9e\u73b0\u516c\u5e73\u6027\u7b56\u7565\u3002\n    \/\/ \u5982\u679c\u5141\u8bb8\u83b7\u53d6\u5199\u9501\uff0c\u5219\u7528 CAS \u66f4\u65b0\u72b6\u6001\u3002\n    if (writerShouldBlock() ||\n        !compareAndSetState(c, c + acquires))\n        return false ; \/\/ \u4e0d\u5141\u8bb8\u83b7\u53d6\u9501 \u6216 CAS \u5931\u8d25\u3002\n\n    \/\/ \u83b7\u53d6\u5199\u9501\u8d85\u8fc7\uff0c\u8bbe\u7f6e\u72ec\u5360\u7ebf\u7a0b\u3002\n    setExclusiveOwnerThread(current);\n    return true;\n}\n\nprotected final boolean tryRelease(int releases) {\n    if (!isHeldExclusively()) \/\/ \u662f\u5426\u662f\u5f53\u524d\u7ebf\u7a0b\u6301\u6709\u5199\u9501\n        throw new IllegalMonitorStateException();\n\n    \/\/ \u8fd9\u91cc\u4e0d\u8003\u8651\u9ad816\u4f4d\u662f\u56e0\u4e3a\u9ad816\u4f4d\u80af\u5b9a\u662f 0\u3002\n    int nextc = getState() - releases;\n    boolean free = exclusiveCount(nextc) == 0;\n    if (free)\n        setExclusiveOwnerThread( null); \/\/ \u5199\u9501\u5b8c\u5168\u91ca\u653e\uff0c\u8bbe\u7f6e\u72ec\u5360\u7ebf\u7a0b\u4e3anull\u3002\n    setState(nextc);\n    return free;\n}\n<\/code><\/pre>\n<h4>\u8bfb\u9501\u83b7\u53d6\u4e0e\u91ca\u653e<\/h4>\n<pre><code class=\"java\">\/\/ \u53c2\u6570\u53d8\u4e3a unused \u662f\u56e0\u4e3a\u8bfb\u9501\u7684\u91cd\u5165\u8ba1\u6570\u662f\u5185\u90e8\u7ef4\u62a4\u7684\u3002\nprotected final int tryAcquireShared(int unused) {\n    Thread current = Thread.currentThread();\n    int c = getState();\n\n    \/\/ \u8fd9\u4e2aif\u8bed\u53e5\u662f\u8bf4\uff1a\u6301\u6709\u5199\u9501\u7684\u7ebf\u7a0b\u53ef\u4ee5\u83b7\u53d6\u8bfb\u9501\u3002\n    if (exclusiveCount(c) != 0 &amp;&amp; \/\/ \u5df2\u5206\u914d\u4e86\u5199\u9501\n        getExclusiveOwnerThread() != current) \/\/ \u4e14\u5f53\u524d\u7ebf\u7a0b\u4e0d\u662f\u6301\u6709\u5199\u9501\u7684\u7ebf\u7a0b\n        return -1;\n\n    int r = sharedCount(c); \/\/ \u53d6\u8bfb\u9501\u8ba1\u6570\n    if (!readerShouldBlock() &amp;&amp; \/\/ \u7531\u5b50\u7c7b\u6839\u636e\u5176\u516c\u5e73\u7b56\u7565\u51b3\u5b9a\u662f\u5426\u5141\u8bb8\u83b7\u53d6\u8bfb\u9501\n        r &lt; MAX_COUNT &amp;&amp;           \/\/ \u8bfb\u9501\u6570\u91cf\u8fd8\u6ca1\u8fbe\u5230\u6700\u5927\u503c\n\n        \/\/ \u5c1d\u8bd5\u83b7\u53d6\u8bfb\u9501\u3002\u6ce8\u610f\u8bfb\u7ebf\u7a0b\u8ba1\u6570\u7684\u5355\u4f4d\u662f  2^16\n        compareAndSetState(c, c + SHARED_UNIT)) {\n         \/\/ \u6210\u529f\u83b7\u53d6\u8bfb\u9501\n\n     \/\/ \u6ce8\u610f\u4e0b\u9762\u5bf9firstReader\u7684\u5904\u7406\uff1afirstReader\u662f\u4e0d\u4f1a\u653e\u5230readHolds\u91cc\u7684\n     \/\/ \u8fd9\u6837\uff0c\u5728\u8bfb\u9501\u53ea\u6709\u4e00\u4e2a\u7684\u60c5\u51b5\u4e0b\uff0c\u5c31\u907f\u514d\u4e86\u67e5\u627ereadHolds\u3002\n        if (r == 0) { \/\/ \u662f firstReader\uff0c\u8ba1\u6570\u4e0d\u4f1a\u653e\u5165  readHolds\u3002\n            firstReader = current;\n            firstReaderHoldCount = 1;\n        } else if (firstReader == current) { \/\/ firstReader \u91cd\u5165\n            firstReaderHoldCount++;\n        } else {\n             \/\/ \u975e firstReader \u8bfb\u9501\u91cd\u5165\u8ba1\u6570\u66f4\u65b0\n            HoldCounter rh = cachedHoldCounter; \/\/ \u9996\u5148\u8bbf\u95ee\u7f13\u5b58\n            if (rh == null || rh.tid != current.getId())\n                cachedHoldCounter = rh = readHolds.get();\n            else if (rh.count == 0)\n                readHolds.set(rh);\n            rh.count++;\n        }\n        return 1;\n    }\n    \/\/ \u83b7\u53d6\u8bfb\u9501\u5931\u8d25\uff0c\u653e\u5230\u5faa\u73af\u91cc\u91cd\u8bd5\u3002\n    return fullTryAcquireShared(current);\n}\n\nfinal int fullTryAcquireShared(Thread current) {\n    HoldCounter rh = null;\n    for (;;) {\n        int c = getState();\n        if (exclusiveCount(c) != 0) {\n            if (getExclusiveOwnerThread() != current)\n           \/\/ \u5199\u9501\u88ab\u5206\u914d\uff0c\u975e\u5199\u9501\u7ebf\u7a0b\u83b7\u53d6\u8bfb\u9501\uff0c\u5931\u8d25\n                return -1;\n            \/\/ \u5426\u5219\uff0c\u5f53\u524d\u7ebf\u7a0b\u6301\u6709\u5199\u9501\uff0c\u5728\u8fd9\u91cc\u963b\u585e\u5c06\u5bfc\u81f4\u6b7b\u9501\u3002\n\n        } else if (readerShouldBlock()) {\n            \/\/ \u5199\u9501\u7a7a\u95f2  \u4e14  \u516c\u5e73\u7b56\u7565\u51b3\u5b9a \u7ebf\u7a0b\u5e94\u5f53\u88ab\u963b\u585e\n            \/\/ \u4e0b\u9762\u7684\u5904\u7406\u662f\u8bf4\uff0c\u5982\u679c\u662f\u5df2\u83b7\u53d6\u8bfb\u9501\u7684\u7ebf\u7a0b\u91cd\u5165\u8bfb\u9501\u65f6\uff0c\n            \/\/ \u5373\u4f7f\u516c\u5e73\u7b56\u7565\u6307\u793a\u5e94\u5f53\u963b\u585e\u4e5f\u4e0d\u4f1a\u963b\u585e\u3002\n            \/\/ \u5426\u5219\uff0c\u8fd9\u4e5f\u4f1a\u5bfc\u81f4\u6b7b\u9501\u7684\u3002\n            if (firstReader == current) {\n                \/\/ assert firstReaderHoldCount &gt; 0;\n            } else {\n                if (rh == null) {\n                    rh = cachedHoldCounter;\n                    if (rh == null || rh.tid != current.getId()) {\n                        rh = readHolds.get();\n                        if (rh.count == 0)\n                            readHolds.remove();\n                    }\n                }\n                \/\/ \u9700\u8981\u963b\u585e\u4e14\u662f\u975e\u91cd\u5165(\u8fd8\u672a\u83b7\u53d6\u8bfb\u9501\u7684)\uff0c\u83b7\u53d6\u5931\u8d25\u3002\n                if (rh.count == 0)\n                    return -1;\n            }\n        }\n\n        \/\/ \u5199\u9501\u7a7a\u95f2  \u4e14  \u516c\u5e73\u7b56\u7565\u51b3\u5b9a\u7ebf\u7a0b\u53ef\u4ee5\u83b7\u53d6\u8bfb\u9501\n        if (sharedCount(c) == MAX_COUNT) \/\/ \u8bfb\u9501\u6570\u91cf\u8fbe\u5230\u6700\u591a\n            throw new Error( \"Maximum lock count exceeded\");\n        if (compareAndSetState(c, c + SHARED_UNIT)) {\n            \/\/ \u7533\u8bf7\u8bfb\u9501\u6210\u529f\uff0c\u4e0b\u9762\u7684\u5904\u7406\u8ddftryAcquireShared\u662f\u7c7b\u4f3c\u7684\u3002\n\n            if (sharedCount(c) == 0) {\n                firstReader = current;\n                firstReaderHoldCount = 1;\n            } else if (firstReader == current) {\n                firstReaderHoldCount++;\n            } else {\n           \/\/ \u8bbe\u5b9a\u6700\u540e\u4e00\u6b21\u83b7\u53d6\u8bfb\u9501\u7684\u7f13\u5b58\n                if (rh == null)\n                    rh = cachedHoldCounter;\n\n                if (rh == null || rh.tid != current.getId())\n                    rh = readHolds.get();\n                else if (rh.count == 0)\n                    readHolds.set(rh);\n                rh.count++;\n\n                cachedHoldCounter = rh; \/\/ \u7f13\u5b58\u8d77\u6765\u7528\u4e8e\u91ca\u653e\n            }\n            return 1;\n        }\n    }\n}\n\nprotected final boolean tryReleaseShared(int unused) {\n    Thread current = Thread.currentThread();\n    \/\/ \u6e05\u7406firstReader\u7f13\u5b58 \u6216 readHolds\u91cc\u7684\u91cd\u5165\u8ba1\u6570\n    if (firstReader == current) {\n        \/\/ assert firstReaderHoldCount &gt; 0;\n        if (firstReaderHoldCount == 1)\n            firstReader = null;\n        else\n            firstReaderHoldCount--;\n    } else {\n        HoldCounter rh = cachedHoldCounter;\n        if (rh == null || rh.tid != current.getId())\n            rh = readHolds.get();\n        int count = rh.count;\n        if (count &lt;= 1) {\n            \/\/ \u5b8c\u5168\u91ca\u653e\u8bfb\u9501\n            readHolds.remove();\n            if (count &lt;= 0)\n                throw unmatchedUnlockException();\n        }\n        --rh.count; \/\/ \u4e3b\u8981\u7528\u4e8e\u91cd\u5165\u9000\u51fa\n    }\n    \/\/ \u5faa\u73af\u5728CAS\u66f4\u65b0\u72b6\u6001\u503c\uff0c\u4e3b\u8981\u662f\u628a\u8bfb\u9501\u6570\u91cf\u51cf 1\n    for (;;) {\n        int c = getState();\n        int nextc = c - SHARED_UNIT;\n        if (compareAndSetState(c, nextc))\n            \/\/ \u91ca\u653e\u8bfb\u9501\u5bf9\u5176\u4ed6\u8bfb\u7ebf\u7a0b\u6ca1\u6709\u4efb\u4f55\u5f71\u54cd\uff0c\n            \/\/ \u4f46\u53ef\u4ee5\u5141\u8bb8\u7b49\u5f85\u7684\u5199\u7ebf\u7a0b\u7ee7\u7eed\uff0c\u5982\u679c\u8bfb\u9501\u3001\u5199\u9501\u90fd\u7a7a\u95f2\u3002\n            return nextc == 0;\n    }\n}\n<\/code><\/pre>\n<h4>\u516c\u5e73\u6027\u7b56\u7565<\/h4>\n<p>\u516c\u5e73\u4e0e\u975e\u516c\u5e73\u7b56\u7565\u662f\u7531 <code>Sync<\/code> \u7684\u5b50\u7c7b <code>FairSync<\/code> \u548c <code>NonfairSync<\/code> \u5b9e\u73b0\u7684\u3002<\/p>\n<pre><code class=\"java\">\/**\n * \u8fd9\u4e2a\u975e\u516c\u5e73\u7b56\u7565\u7684\u540c\u6b65\u5668\u662f\u5199\u9501\u4f18\u5148\u7684\uff0c\u7533\u8bf7\u5199\u9501\u65f6\u603b\u662f\u4e0d\u963b\u585e\u3002\n *\/\nstatic final class NonfairSync extends Sync {\n    private static final long serialVersionUID = -8159625535654395037L;\n    final boolean writerShouldBlock() {\n        return false; \/\/ \u5199\u7ebf\u7a0b\u603b\u662f\u53ef\u4ee5\u7a81\u5165\n    }\n    final boolean readerShouldBlock() {\n        \/* \u4f5c\u4e3a\u4e00\u4e2a\u542f\u53d1\u7528\u4e8e\u907f\u514d\u5199\u7ebf\u7a0b\u9965\u997f\uff0c\u5982\u679c\u7ebf\u7a0b\u4e34\u65f6\u51fa\u73b0\u5728\u7b49\u5f85\u961f\u5217\u7684\u5934\u90e8\u5219\u963b\u585e\uff0c\n         * \u5982\u679c\u5b58\u5728\u8fd9\u6837\u7684\uff0c\u5219\u662f\u5199\u7ebf\u7a0b\u3002\n         *\/\n        return apparentlyFirstQueuedIsExclusive();\n    }\n}\n\n\/**\n * \u516c\u5e73\u7684 Sync\uff0c\u5b83\u7684\u7b56\u7565\u662f\uff1a\u5982\u679c\u7ebf\u7a0b\u51c6\u5907\u83b7\u53d6\u9501\u65f6\uff0c\n * \u540c\u6b65\u961f\u5217\u91cc\u6709\u7b49\u5f85\u7ebf\u7a0b\uff0c\u5219\u963b\u585e\u83b7\u53d6\u9501\uff0c\u4e0d\u7ba1\u662f\u5426\u662f\u91cd\u5165\n * \u8fd9\u4e5f\u5c31\u9700\u8981tryAcqire\u3001tryAcquireShared\u65b9\u6cd5\u8fdb\u884c\u5904\u7406\u3002\n *\/\nstatic final class FairSync extends Sync {\n    private static final long serialVersionUID = -2274990926593161451L;\n    final boolean writerShouldBlock() {\n        return hasQueuedPredecessors();\n    }\n    final boolean readerShouldBlock() {\n        return hasQueuedPredecessors();\n    }\n}\n<\/code><\/pre>\n<p>\u73b0\u5728\u7528\u5947\u6570\u8868\u793a\u7533\u8bf7\u8bfb\u9501\u7684\u8bfb\u7ebf\u7a0b\uff0c\u5076\u6570\u8868\u793a\u7533\u8bf7\u5199\u9501\u7684\u5199\u7ebf\u7a0b\uff0c\u6bcf\u4e2a\u6570\u90fd\u8868\u793a\u4e00\u4e2a\u4e0d\u540c\u7684\u7ebf\u7a0b\uff0c\u5b58\u5728\u4e0b\u9762\u8fd9\u6837\u7684\u7533\u8bf7\u961f\u5217\uff0c\u5047\u8bbe\u5f00\u59cb\u65f6\u9501\u7a7a\u95f2\uff1a<\/p>\n<pre>\n1  3  5  0  7  9  2  4\n<\/pre>\n<p>\u8bfb\u7ebf\u7a0b1\u7533\u8bf7\u8bfb\u9501\u65f6\uff0c\u9501\u662f\u7a7a\u95f2\u7684\uff0c\u9a6c\u4e0a\u5206\u914d\uff0c\u8bfb\u7ebf\u7a0b3\u30015\u7533\u8bf7\u65f6\uff0c\u7531\u4e8e\u5df2\u5206\u914d\u8bfb\u9501\uff0c\u5b83\u4eec\u4e5f\u53ef\u4ee5\u9a6c\u4e0a\u83b7\u53d6\u8bfb\u9501\u3002<br \/>\n\u5bf9\u4e8e\u516c\u5e73\u9501\uff0c\u5047\u8bbe\u6b64\u65f6\u6709\u7ebf\u7a0b11\u7533\u8bf7\u8bfb\u9501\uff0c\u7531\u4e8e\u5b83\u4e0d\u662f\u8bfb\u9501\u91cd\u5165\u4e14\u524d\u9762\u6709\u7b49\u5f85\u7ebf\u7a0b\uff0c\u53ea\u80fd\u7b49\u5f85\u3002\u800c\u7ebf\u7a0b1\u518d\u6b21\u7533\u8bf7\u8bfb\u9501\u662f\u53ef\u4ee5\u7684\uff0c\u56e0\u4e3a\u5b83\u7684\u91cd\u5165\u3002<br \/>\n\u5199\u7ebf\u7a0b0\u7533\u8bf7\u5199\u9501\u65f6\uff0c\u7531\u4e8e\u5206\u914d\u4e86\u8bfb\u9501\uff0c\u53ea\u80fd\u7b49\u5f85\uff0c\u5f53\u8bfb\u7ebf\u7a0b1\u30013\u30015\u90fd\u91ca\u653e\u8bfb\u9501\u540e\uff0c\u7ebf\u7a0b0\u53ef\u4ee5\u83b7\u53d6\u5199\u9501\u3002<br \/>\n\u7ebf\u7a0b0\u91ca\u653e\u540e\uff0c\u7ebf\u7a0b7\u30019\u83b7\u53d6\u8bfb\u9501\uff0c\u5b83\u4eec\u91ca\u653e\u540e\uff0c\u7ebf\u7a0b2\u83b7\u53d6\u5199\u9501\uff0c\u6b64\u65f6\u7ebf\u7a0b4\u5fc5\u987b\u7b49\u5f85\u7ebf\u7a0b2\u91ca\u653e\u3002<br \/>\n\u7ebf\u7a0b4\u5728\u7ebf\u7a0b2\u91ca\u653e\u5199\u9501\u540e\u83b7\u53d6\u5199\u9501\uff0c\u5b83\u91ca\u653e\u5199\u9501\u540e\uff0c\u9501\u6062\u590d\u7a7a\u95f2\u3002<\/p>\n<hr\/>\n<p>\u6b22\u8fce\u5173\u6ce8\u6211\u7684\u5fae\u4fe1\u516c\u4f17\u53f7: <strong>coderbee\u7b14\u8bb0<\/strong>\uff0c\u53ef\u4ee5\u66f4\u53ca\u65f6\u56de\u590d\u4f60\u7684\u8ba8\u8bba\u3002<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"258\" height=\"258\" src=\"https:\/\/coderbee.net\/wp-content\/uploads\/2019\/01\/coderbee-note.jpg\" class=\"alignnone size-full wp-image-1707\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u8bfb\u5199\u9501 ReadWriteLock \u8bfb\u5199\u9501\u7ef4\u62a4\u4e86\u4e00\u5bf9\u76f8\u5173\u7684\u9501\uff0c\u4e00\u4e2a\u7528\u4e8e\u53ea\u8bfb\u64cd\u4f5c\uff0c &hellip; <a href=\"https:\/\/coderbee.net\/index.php\/concurrent\/20140214\/792\">\u7ee7\u7eed\u9605\u8bfb <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[121],"tags":[110,155,154],"_links":{"self":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/792"}],"collection":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/comments?post=792"}],"version-history":[{"count":7,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/792\/revisions"}],"predecessor-version":[{"id":816,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/792\/revisions\/816"}],"wp:attachment":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/media?parent=792"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/categories?post=792"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/tags?post=792"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}