{"id":10008387,"date":"2024-02-22T17:05:28","date_gmt":"2024-02-22T09:05:28","guid":{"rendered":"https:\/\/blog.itmax.cn\/?p=10008387"},"modified":"2024-02-22T17:05:28","modified_gmt":"2024-02-22T09:05:28","slug":"%e9%9d%a2%e8%af%95%e5%ae%98%ef%bc%9a%e4%bb%80%e4%b9%88%e6%98%afjava%e5%86%85%e5%ad%98%e6%a8%a1%e5%9e%8b%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/itmax.cn\/?p=10008387","title":{"rendered":"\u9762\u8bd5\u5b98\uff1a\u4ec0\u4e48\u662fJava\u5185\u5b58\u6a21\u578b\uff1f"},"content":{"rendered":"<p>\u5f53\u95ee\u5230 Java \u5185\u5b58\u6a21\u578b\u7684\u65f6\u5019\uff0c\u4e00\u5b9a\u8981\u6ce8\u610f\uff0cJava \u5185\u5b58\u6a21\u578b\uff08Java Memory Model\uff0cJMM\uff09\u5b83\u548c JVM \u5185\u5b58\u5e03\u5c40\uff08JVM \u8fd0\u884c\u65f6\u6570\u636e\u533a\u57df\uff09\u662f\u4e0d\u4e00\u6837\u7684\uff0c\u5b83\u4eec\u662f\u4e24\u4e2a\u5b8c\u5168\u4e0d\u540c\u7684\u6982\u5ff5\u3002<\/p>\n<h2>1.\u4e3a\u4ec0\u4e48\u8981\u6709 Java \u5185\u5b58\u6a21\u578b\uff1f<\/h2>\n<p>Java \u5185\u5b58\u6a21\u578b\u5b58\u5728\u7684\u539f\u56e0\u5728\u4e8e\u89e3\u51b3\u591a\u7ebf\u7a0b\u73af\u5883\u4e0b\u5e76\u53d1\u6267\u884c\u65f6\u7684\u5185\u5b58\u53ef\u89c1\u6027\u548c\u4e00\u81f4\u6027\u95ee\u9898\u3002\u5728\u73b0\u4ee3\u8ba1\u7b97\u673a\u7cfb\u7edf\u4e2d\uff0c\u5c24\u5176\u662f\u591a\u5904\u7406\u5668\u67b6\u6784\u4e0b\uff0c\u6bcf\u4e2a\u5904\u7406\u5668\u90fd\u6709\u81ea\u5df1\u7684\u9ad8\u901f\u7f13\u5b58\uff0c\u800c\u4e3b\u5185\u5b58\uff08RAM\uff09\u662f\u6240\u6709\u5904\u7406\u5668\u5171\u4eab\u7684\u6570\u636e\u5b58\u50a8\u533a\u57df\u3002\u5f53\u591a\u4e2a\u7ebf\u7a0b\u540c\u65f6\u8bbf\u95ee\u548c\u4fee\u6539\u540c\u4e00\u5757\u5171\u4eab\u6570\u636e\u65f6\uff0c\u5982\u679c\u6ca1\u6709\u9002\u5f53\u7684\u540c\u6b65\u673a\u5236\uff0c\u5c31\u53ef\u80fd\u5bfc\u81f4\u4ee5\u4e0b\u95ee\u9898\uff1a<\/p>\n<ol>\n<li><strong>\u53ef\u89c1\u6027<\/strong>\uff1a\u4e00\u4e2a\u7ebf\u7a0b\u5bf9\u5171\u4eab\u53d8\u91cf\u6240\u505a\u7684\u4fee\u6539\u53ef\u80fd\u4e0d\u4f1a\u7acb\u5373\u53cd\u6620\u5230\u53e6\u4e00\u4e2a\u7ebf\u7a0b\u7684\u89c6\u89d2\u4e2d\uff0c\u56e0\u4e3a\u8fd9\u4e9b\u4fee\u6539\u53ef\u80fd\u53ea\u5b58\u5728\u4e8e\u672c\u5730\u7f13\u5b58\u4e2d\uff0c\u5e76\u672a\u5237\u65b0\u56de\u4e3b\u5185\u5b58\u3002<\/li>\n<li><strong>\u6709\u5e8f\u6027<\/strong>\uff1a\u7f16\u8bd1\u5668\u548c\u5904\u7406\u5668\u4e3a\u4e86\u4f18\u5316\u6027\u80fd\uff0c\u53ef\u80fd\u4f1a\u5bf9\u6307\u4ee4\u8fdb\u884c\u91cd\u6392\u5e8f\uff0c\u8fd9\u53ef\u80fd\u5bfc\u81f4\u7a0b\u5e8f\u5728\u5355\u7ebf\u7a0b\u73af\u5883\u4e2d\u770b\u4f3c\u6309\u7167\u6e90\u4ee3\u7801\u987a\u5e8f\u6267\u884c\uff0c\u4f46\u5728\u591a\u7ebf\u7a0b\u73af\u5883\u4e2d\u7684\u5b9e\u9645\u6267\u884c\u987a\u5e8f\u5374\u4e0e\u9884\u671f\u4e0d\u540c\u3002<\/li>\n<li><strong>\u539f\u5b50\u6027<\/strong>\uff1a\u5373\u4f7f\u662f\u6700\u7b80\u5355\u7684\u8bfb\u53d6\u6216\u8d4b\u503c\u64cd\u4f5c\uff0c\u5728\u786c\u4ef6\u5c42\u9762\u4e5f\u4e0d\u4e00\u5b9a\u4fdd\u8bc1\u662f\u539f\u5b50\u6027\u7684\uff0c\u5373\u5728\u6ca1\u6709\u540c\u6b65\u7684\u60c5\u51b5\u4e0b\uff0c\u591a\u7ebf\u7a0b\u4e0b\u53ef\u80fd\u770b\u5230\u64cd\u4f5c\u53ea\u6267\u884c\u4e86\u4e00\u90e8\u5206\u7684\u7ed3\u679c\u3002<\/li>\n<\/ol>\n<p>Java \u5185\u5b58\u6a21\u578b\u901a\u8fc7\u5b9a\u4e49\u4e00\u5957\u89c4\u5219\u6765\u89c4\u8303\u5e76\u9650\u5236\u7f16\u8bd1\u5668\u3001\u8fd0\u884c\u65f6\u4ee5\u53ca\u5904\u7406\u5668\u5bf9\u5185\u5b58\u8bbf\u95ee\u7684\u91cd\u6392\u5e8f\u884c\u4e3a\uff0c\u786e\u4fdd\u4e86\u591a\u7ebf\u7a0b\u95f4\u7684\u4ea4\u4e92\u5177\u6709\u660e\u786e\u7684\u8bed\u4e49\u3002\u5b83\u89c4\u5b9a\u4e86\u5171\u4eab\u53d8\u91cf\u7684\u8bbf\u95ee\u89c4\u5219\u3001\u63d0\u4f9b\u4e86 happens-before \u539f\u5219\u4ee5\u53ca volatile \u5173\u952e\u5b57\u3001synchronized \u7b49\u5de5\u5177\u6765\u5b9e\u73b0\u5185\u5b58\u53ef\u89c1\u6027\u548c\u4e00\u81f4\u6027\u7684\u4fdd\u969c\u3002\u8fd9\u6837\uff0c\u7a0b\u5e8f\u5458\u5728\u7f16\u5199\u5e76\u53d1\u4ee3\u7801\u65f6\uff0c\u53ef\u4ee5\u4f9d\u636e\u8fd9\u4e9b\u89c4\u5219\u6765\u786e\u4fdd\u4ee3\u7801\u7684\u6b63\u786e\u6267\u884c\uff0c\u4ece\u800c\u907f\u514d\u7531\u4e8e\u591a\u7ebf\u7a0b\u5e26\u6765\u7684\u4e0d\u786e\u5b9a\u6027\u548c\u9519\u8bef\u3002<\/p>\n<p>\u5982\u679c\u6ca1\u6709 Java \u5185\u5b58\u6a21\u578b\u5c31\u4f1a\u51fa\u73b0\u4ee5\u4e0b\u4e24\u5927\u95ee\u9898\uff1a<\/p>\n<ol>\n<li>CPU \u548c \u5185\u5b58\u4e00\u81f4\u6027\u95ee\u9898\u3002<\/li>\n<li>\u6307\u4ee4\u91cd\u6392\u5e8f\u95ee\u9898\u3002<\/li>\n<\/ol>\n<p>\u5177\u4f53\u5185\u5bb9\u5982\u4e0b\u3002<\/p>\n<h3>1.1 \u4e00\u81f4\u6027\u95ee\u9898<\/h3>\n<p>\u8981\u8bb2\u660e\u767d\u7f13\u5b58\u4e00\u81f4\u6027\u95ee\u9898\uff0c\u8981\u4ece\u8ba1\u7b97\u673a\u7684\u5185\u5b58\u7ed3\u6784\u8bf4\u8d77\uff0c\u5b83\u7684\u7ed3\u6784\u662f\u8fd9\u6837\u7684\uff1a<br \/><img decoding=\"async\"   referrerpolicy=\"no-referrer\" src=\"https:\/\/cdn.nlark.com\/yuque\/0\/2024\/png\/92791\/1708575523698-d7ee0392-391e-4164-8ceb-2d122671fd86.png#averageHue=%23e9dfc7&#038;clientId=u197e7386-25b0-4&#038;from=paste&#038;height=498&#038;id=u5c56ecf6&#038;originHeight=747&#038;originWidth=995&#038;originalType=binary&#038;ratio=1.5&#038;rotation=0&#038;showTitle=false&#038;size=503306&#038;status=done&#038;style=none&#038;taskId=u831f472a-92c7-4901-be4d-ef354b731ec&#038;title=&#038;width=663.3333333333334\" alt=\"image.png\" title=\"image.png\"><br \/>\u6240\u4ee5\u4ece\u4e0a\u9762\u53ef\u4ee5\u770b\u51fa\u8ba1\u7b97\u673a\u7684\u91cd\u8981\u7ec4\u6210\u90e8\u5206\u5305\u542b\u4ee5\u4e0b\u5185\u5bb9\uff1a<\/p>\n<ol>\n<li>CPU<\/li>\n<li>CPU \u5bc4\u5b58\u5668\uff1a\u4e5f\u53eb L1 \u7f13\u5b58\uff0c\u4e00\u7ea7\u7f13\u5b58\u3002<\/li>\n<li>CPU \u9ad8\u901f\u7f13\u5b58\uff1a\u4e5f\u53eb L2 \u7f13\u5b58\uff0c\u4e8c\u7ea7\u7f13\u5b58\u3002<\/li>\n<li>\uff08\u4e3b\uff09\u5185\u5b58<\/li>\n<\/ol>\n<p>\u5f53\u7136\uff0c\u90e8\u5206\u9ad8\u7aef\u673a\u5668\u8fd8\u6709 L3 \u4e09\u7ea7\u7f13\u5b58\u3002<\/p>\n<p>\u7531\u4e8e\u4e3b\u5185\u5b58\u4e0e CPU \u5904\u7406\u5668\u7684\u8fd0\u7b97\u80fd\u529b\u4e4b\u95f4\u6709\u6570\u91cf\u7ea7\u7684\u5dee\u8ddd\uff0c\u6240\u4ee5\u5728\u4f20\u7edf\u8ba1\u7b97\u673a\u5185\u5b58\u67b6\u6784\u4e2d\u4f1a\u5f15\u5165\u9ad8\u901f\u7f13\u5b58\uff08L2\uff09\u6765\u4f5c\u4e3a\u4e3b\u5b58\u548c\u5904\u7406\u5668\u4e4b\u95f4\u7684\u7f13\u51b2\uff0cCPU \u5c06\u5e38\u7528\u7684\u6570\u636e\u653e\u5728\u9ad8\u901f\u7f13\u5b58\u4e2d\uff0c\u8fd0\u7b97\u7ed3\u675f\u540e CPU \u518d\u8bb2\u8fd0\u7b97\u7ed3\u679c\u540c\u6b65\u5230\u4e3b\u5185\u5b58\u4e2d\uff0c\u8fd9\u6837\u5c31\u4f1a\u5bfc\u81f4\u591a\u4e2a\u7ebf\u7a0b\u5728\u8fdb\u884c\u64cd\u4f5c\u548c\u540c\u6b65\u65f6\uff0c\u5bfc\u81f4 CPU \u7f13\u5b58\u548c\u4e3b\u5185\u5b58\u6570\u636e\u4e0d\u4e00\u81f4\u7684\u95ee\u9898\u3002<\/p>\n<h3>1.2 \u91cd\u6392\u5e8f\u95ee\u9898<\/h3>\n<p>\u7531\u4e8e\u6709 JIT\uff08Just In Time\uff0c\u5373\u65f6\u7f16\u8bd1\uff09\u6280\u672f\u7684\u5b58\u5728\uff0c\u5b83\u53ef\u80fd\u4f1a\u5bf9\u4ee3\u7801\u8fdb\u884c\u4f18\u5316\uff0c\u6bd4\u5982\u5c06\u539f\u672c\u6267\u884c\u987a\u5e8f\u4e3a a -&gt; b -&gt; c \u7684\u6d41\u7a0b\uff0c\u201c\u4f18\u5316\u201d\u6210 a -&gt; c -&gt; b \u4e86\uff0c\u4f46\u8fd9\u6837\u4f18\u5316\u4e4b\u540e\uff0c\u53ef\u80fd\u4f1a\u5bfc\u81f4\u6211\u4eec\u7684\u7a0b\u5e8f\u5728\u67d0\u4e9b\u573a\u666f\u6267\u884c\u51fa\u9519\uff0c\u6bd4\u5982\u5355\u4f8b\u6a21\u5f0f\u53cc\u91cd\u6548\u9a8c\u9501\u7684\u573a\u666f\uff0c\u8fd9\u5c31\u662f\u5178\u578b\u7684\u597d\u5fc3\u529e\u574f\u4e8b\u7684\u4e8b\u4f8b\u3002<\/p>\n<h2>2.\u5b9a\u4e49<\/h2>\n<p>Java \u5185\u5b58\u6a21\u578b\uff08Java Memory Model\uff0c\u7b80\u79f0 JMM\uff09\u662f\u4e00\u79cd\u89c4\u8303\uff0c\u5b83\u5b9a\u4e49\u4e86 Java \u865a\u62df\u673a\uff08JVM\uff09\u5728\u8ba1\u7b97\u673a\u5185\u5b58\uff08RAM\uff09\u4e2d\u7684\u5de5\u4f5c\u65b9\u5f0f\uff0c\u5373<strong>\u89c4\u8303\u4e86 Java \u865a\u62df\u673a\u4e0e\u8ba1\u7b97\u673a\u5185\u5b58\u4e4b\u95f4\u662f\u5982\u4f55\u534f\u540c\u5de5\u4f5c\u7684<\/strong>\u3002\u5177\u4f53\u6765\u8bf4\uff0c\u5b83\u89c4\u5b9a\u4e86\u4e00\u4e2a\u7ebf\u7a0b\u5982\u4f55\u548c\u4f55\u65f6\u53ef\u4ee5\u770b\u5230\u5176\u4ed6\u7ebf\u7a0b\u4fee\u6539\u8fc7\u7684\u5171\u4eab\u53d8\u91cf\u7684\u503c\uff0c\u4ee5\u53ca\u5728\u5fc5\u987b\u65f6\u5982\u4f55\u540c\u6b65\u5730\u8bbf\u95ee\u5171\u4eab\u53d8\u91cf\u3002<\/p>\n<h2>3.\u89c4\u8303\u5185\u5bb9<\/h2>\n<p>Java \u5185\u5b58\u6a21\u578b\u4e3b\u8981\u5305\u62ec\u4ee5\u4e0b\u5185\u5bb9\uff1a<\/p>\n<ol>\n<li><strong>\u4e3b\u5185\u5b58\uff08Main Memory\uff09<\/strong>\uff1a\u6240\u6709\u7ebf\u7a0b\u5171\u4eab\u7684\u5185\u5b58\u533a\u57df\uff0c\u5305\u542b\u4e86\u5bf9\u8c61\u7684\u5b57\u6bb5\u3001\u65b9\u6cd5\u548c\u8fd0\u884c\u65f6\u5e38\u91cf\u6c60\u7b49\u6570\u636e\u3002<\/li>\n<li><strong>\u5de5\u4f5c\u5185\u5b58\uff08Working Memory\uff09<\/strong>\uff1a\u6bcf\u4e2a\u7ebf\u7a0b\u62e5\u6709\u81ea\u5df1\u7684\u5de5\u4f5c\u5185\u5b58\uff0c\u7528\u4e8e\u5b58\u50a8\u4e3b\u5185\u5b58\u4e2d\u7684\u6570\u636e\u7684\u526f\u672c\uff0c\u7ebf\u7a0b\u53ea\u80fd\u76f4\u63a5\u64cd\u4f5c\u5de5\u4f5c\u5185\u5b58\u4e2d\u7684\u6570\u636e\u3002<\/li>\n<li><strong>\u5185\u5b58\u95f4\u4ea4\u4e92\u64cd\u4f5c<\/strong>\uff1a\u7ebf\u7a0b\u901a\u8fc7\u8bfb\u53d6\u548c\u5199\u5165\u64cd\u4f5c\u4e0e\u4e3b\u5185\u5b58\u8fdb\u884c\u4ea4\u4e92\u3002\u8bfb\u64cd\u4f5c\u5c06\u6570\u636e\u4ece\u4e3b\u5185\u5b58\u590d\u5236\u5230\u5de5\u4f5c\u5185\u5b58\uff0c\u5199\u64cd\u4f5c\u5c06\u4fee\u6539\u540e\u7684\u6570\u636e\u5237\u65b0\u5230\u4e3b\u5185\u5b58\u3002<\/li>\n<li><strong>\u539f\u5b50\u6027\uff08Atomicity\uff09<\/strong>\uff1aJMM \u4fdd\u8bc1\u57fa\u672c\u6570\u636e\u7c7b\u578b\uff08\u5982 int\u3001long\uff09\u7684\u8bfb\u5199\u64cd\u4f5c\u5177\u6709\u539f\u5b50\u6027\uff0c\u5373\u4e0d\u4f1a\u88ab\u5176\u4ed6\u7ebf\u7a0b\u5e72\u6270\uff0c\u4fdd\u8bc1\u64cd\u4f5c\u7684\u5b8c\u6574\u6027\u3002<\/li>\n<li><strong>\u53ef\u89c1\u6027\uff08Visibility\uff09<\/strong>\uff1aJMM \u786e\u4fdd\u4e00\u4e2a\u7ebf\u7a0b\u5bf9\u5171\u4eab\u53d8\u91cf\u7684\u4fee\u6539\u5bf9\u5176\u4ed6\u7ebf\u7a0b\u53ef\u89c1\u3002\u8fd9\u610f\u5473\u7740\u4e00\u4e2a\u7ebf\u7a0b\u5728\u5de5\u4f5c\u5185\u5b58\u4e2d\u4fee\u6539\u4e86\u6570\u636e\u540e\uff0c\u5fc5\u987b\u5c06\u6700\u65b0\u7684\u6570\u636e\u5237\u65b0\u5230\u4e3b\u5185\u5b58\uff0c\u4ee5\u4fbf\u5176\u4ed6\u7ebf\u7a0b\u53ef\u4ee5\u8bfb\u53d6\u5230\u66f4\u65b0\u540e\u7684\u6570\u636e\u3002<\/li>\n<li><strong>\u6709\u5e8f\u6027\uff08Ordering\uff09<\/strong>\uff1aJMM \u4fdd\u8bc1\u7a0b\u5e8f\u7684\u6267\u884c\u987a\u5e8f\u6309\u7167\u4e00\u5b9a\u7684\u89c4\u5219\u8fdb\u884c\uff0c\u4e0d\u4f1a\u51fa\u73b0\u968f\u673a\u7684\u91cd\u6392\u5e8f\u73b0\u8c61\u3002\u8fd9\u5305\u62ec\u4e86\u7f16\u8bd1\u5668\u91cd\u6392\u5e8f\u3001\u5904\u7406\u5668\u91cd\u6392\u5e8f\u548c\u5185\u5b58\u91cd\u6392\u5e8f\u7b49\u3002<\/li>\n<\/ol>\n<p>Java \u5185\u5b58\u6a21\u578b\u901a\u8fc7\u4ee5\u4e0a\u89c4\u5219\u548c\u8bed\u4e49\uff0c\u63d0\u4f9b\u4e86\u4e00\u79cd\u7edf\u4e00\u7684\u5185\u5b58\u8bbf\u95ee\u65b9\u5f0f\uff0c\u4f7f\u5f97\u591a\u7ebf\u7a0b\u7a0b\u5e8f\u7684\u884c\u4e3a\u53ef\u9884\u6d4b\u3001\u53ef\u7406\u89e3\uff0c\u5e76\u5e2e\u52a9\u5f00\u53d1\u8005\u7f16\u5199\u6b63\u786e\u548c\u9ad8\u6548\u7684\u591a\u7ebf\u7a0b\u4ee3\u7801\u3002\u5f00\u53d1\u8005\u53ef\u4ee5\u5229\u7528 JMM \u63d0\u4f9b\u7684\u540c\u6b65\u673a\u5236\uff08\u5982\u5173\u952e\u5b57 volatile\u3001synchronized\u3001Lock \u7b49\uff09\u6765\u5b9e\u73b0\u7ebf\u7a0b\u4e4b\u95f4\u7684\u540c\u6b65\u548c\u901a\u4fe1\uff0c\u4ee5\u786e\u4fdd\u7ebf\u7a0b\u5b89\u5168\u548c\u6570\u636e\u4e00\u81f4\u6027\u3002<\/p>\n<p>\u5185\u5b58\u6a21\u578b\u7684\u7b80\u5355\u6267\u884c\u793a\u4f8b\u56fe\u5982\u4e0b\uff1a<br \/><img decoding=\"async\"   referrerpolicy=\"no-referrer\" src=\"https:\/\/cdn.nlark.com\/yuque\/0\/2024\/png\/92791\/1708575146057-3b657f36-e244-4cc6-b86a-1b2820d0ac73.png#averageHue=%23f9f4f2&#038;clientId=u197e7386-25b0-4&#038;from=paste&#038;height=507&#038;id=ue9f2b7e2&#038;originHeight=760&#038;originWidth=814&#038;originalType=binary&#038;ratio=1.5&#038;rotation=0&#038;showTitle=false&#038;size=373277&#038;status=done&#038;style=none&#038;taskId=u6b9c65c7-7d3a-4d28-aaad-a6235225492&#038;title=&#038;width=542.6666666666666\" alt=\"image.png\" title=\"image.png\" loading=\"lazy\"><\/p>\n<h3>3.1 \u4e3b\u5185\u5b58\u548c\u5de5\u4f5c\u5185\u5b58\u4ea4\u4e92\u89c4\u8303<\/h3>\n<p>\u4e3a\u4e86\u66f4\u597d\u7684\u63a7\u5236\u4e3b\u5185\u5b58\u548c\u672c\u5730\u5185\u5b58\u7684\u4ea4\u4e92\uff0cJava \u5185\u5b58\u6a21\u578b\u5b9a\u4e49\u4e86\u516b\u79cd\u64cd\u4f5c\u6765\u5b9e\u73b0\uff08\u4ee5\u4e0b\u5185\u5bb9\u53ea\u9700\u8981\u7b80\u5355\u4e86\u89e3\u5373\u53ef\uff09\uff1a<\/p>\n<ol>\n<li><strong>lock\uff08\u9501\u5b9a\uff09<\/strong>\uff1a\u4f5c\u7528\u4e8e\u4e3b\u5185\u5b58\u7684\u53d8\u91cf\uff0c\u628a\u4e00\u4e2a\u53d8\u91cf\u6807\u8bc6\u4e3a\u4e00\u6761\u7ebf\u7a0b\u72ec\u5360\u72b6\u6001\u3002<\/li>\n<li><strong>unlock\uff08\u89e3\u9501\uff09<\/strong>\uff1a\u4f5c\u7528\u4e8e\u4e3b\u5185\u5b58\u53d8\u91cf\uff0c\u628a\u4e00\u4e2a\u5904\u4e8e\u9501\u5b9a\u72b6\u6001\u7684\u53d8\u91cf\u91ca\u653e\u51fa\u6765\uff0c\u91ca\u653e\u540e\u7684\u53d8\u91cf\u624d\u53ef\u4ee5\u88ab\u5176\u4ed6\u7ebf\u7a0b\u9501\u5b9a\u3002<\/li>\n<li><strong>read\uff08\u8bfb\u53d6\uff09<\/strong>\uff1a\u4f5c\u7528\u4e8e\u4e3b\u5185\u5b58\u53d8\u91cf\uff0c\u628a\u4e00\u4e2a\u53d8\u91cf\u503c\u4ece\u4e3b\u5185\u5b58\u4f20\u8f93\u5230\u7ebf\u7a0b\u7684\u5de5\u4f5c\u5185\u5b58\u4e2d\uff0c\u4ee5\u4fbf\u968f\u540e\u7684 load \u52a8\u4f5c\u4f7f\u7528<\/li>\n<li><strong>load\uff08\u8f7d\u5165\uff09<\/strong>\uff1a\u4f5c\u7528\u4e8e\u5de5\u4f5c\u5185\u5b58\u7684\u53d8\u91cf\uff0c\u5b83\u628a read \u64cd\u4f5c\u4ece\u4e3b\u5185\u5b58\u4e2d\u5f97\u5230\u7684\u53d8\u91cf\u503c\u653e\u5165\u5de5\u4f5c\u5185\u5b58\u7684\u53d8\u91cf\u526f\u672c\u4e2d\u3002<\/li>\n<li><strong>use\uff08\u4f7f\u7528\uff09<\/strong>\uff1a\u4f5c\u7528\u4e8e\u5de5\u4f5c\u5185\u5b58\u7684\u53d8\u91cf\uff0c\u628a\u5de5\u4f5c\u5185\u5b58\u4e2d\u7684\u4e00\u4e2a\u53d8\u91cf\u503c\u4f20\u9012\u7ed9\u6267\u884c\u5f15\u64ce\uff0c\u6bcf\u5f53\u865a\u62df\u673a\u9047\u5230\u4e00\u4e2a\u9700\u8981\u4f7f\u7528\u53d8\u91cf\u7684\u503c\u7684\u5b57\u8282\u7801\u6307\u4ee4\u65f6\u5c06\u4f1a\u6267\u884c\u8fd9\u4e2a\u64cd\u4f5c\u3002<\/li>\n<li><strong>assign\uff08\u8d4b\u503c\uff09<\/strong>\uff1a\u4f5c\u7528\u4e8e\u5de5\u4f5c\u5185\u5b58\u7684\u53d8\u91cf\uff0c\u5b83\u628a\u4e00\u4e2a\u4ece\u6267\u884c\u5f15\u64ce\u63a5\u6536\u5230\u7684\u503c\u8d4b\u503c\u7ed9\u5de5\u4f5c\u5185\u5b58\u7684\u53d8\u91cf\uff0c\u6bcf\u5f53\u865a\u62df\u673a\u9047\u5230\u4e00\u4e2a\u7ed9\u53d8\u91cf\u8d4b\u503c\u7684\u5b57\u8282\u7801\u6307\u4ee4\u65f6\u6267\u884c\u8fd9\u4e2a\u64cd\u4f5c\u3002<\/li>\n<li><strong>store\uff08\u5b58\u50a8\uff09<\/strong>\uff1a\u4f5c\u7528\u4e8e\u5de5\u4f5c\u5185\u5b58\u7684\u53d8\u91cf\uff0c\u628a\u5de5\u4f5c\u5185\u5b58\u4e2d\u7684\u4e00\u4e2a\u53d8\u91cf\u7684\u503c\u4f20\u9001\u5230\u4e3b\u5185\u5b58\u4e2d\uff0c\u4ee5\u4fbf\u968f\u540e\u7684write\u7684\u64cd\u4f5c\u3002<\/li>\n<li>\n<p><strong>write\uff08\u5199\u5165\uff09<\/strong>\uff1a\u4f5c\u7528\u4e8e\u4e3b\u5185\u5b58\u7684\u53d8\u91cf\uff0c\u5b83\u628a store \u64cd\u4f5c\u4ece\u5de5\u4f5c\u5185\u5b58\u4e2d\u4e00\u4e2a\u53d8\u91cf\u7684\u503c\u4f20\u9001\u5230\u4e3b\u5185\u5b58\u7684\u53d8\u91cf\u4e2d\u3002<\/p>\n<blockquote><p>PS\uff1a\u5de5\u4f5c\u5185\u5b58\u4e5f\u5c31\u662f\u672c\u5730\u5185\u5b58\u7684\u610f\u601d\u3002<\/p><\/blockquote>\n<\/li>\n<\/ol>\n<h3>3.2 \u4ec0\u4e48\u662f happens-before \u539f\u5219\uff1f<\/h3>\n<p>happens-before\uff08\u5148\u884c\u53d1\u751f\uff09\u539f\u5219\u662f Java \u5185\u5b58\u6a21\u578b\u4e2d\u5b9a\u4e49\u7684\u7528\u4e8e\u4fdd\u8bc1\u591a\u7ebf\u7a0b\u73af\u5883\u4e0b\u64cd\u4f5c\u6267\u884c\u987a\u5e8f\u548c\u53ef\u89c1\u6027\u7684\u4e00\u79cd\u91cd\u8981\u624b\u6bb5\u3002<\/p>\n<p>\u4e3e\u4e2a\u4f8b\u5b50\u6765\u8bf4\uff0c\u4f8b\u5982 A happens-before B\uff0c\u4e5f\u5c31\u662f A \u7ebf\u7a0b\u65e9\u4e8e B \u7ebf\u7a0b\u6267\u884c\uff0c\u90a3\u4e48 A happens-before B \u53ef\u4ee5\u4fdd\u969c\u4ee5\u4e0b\u4e24\u9879\u5185\u5bb9\uff1a<\/p>\n<ul>\n<li><strong>\u53ef\u89c1\u6027<\/strong>\uff1aB \u8bfb\u53d6\u5230 A \u6700\u65b0\u4fee\u6539\u7684\u503c\uff08\u901a\u8fc7\u5185\u5b58\u5c4f\u969c\uff09\u3002<\/li>\n<li>\n<p><strong>\u987a\u5e8f\u6027<\/strong>\uff1a\u7f16\u8bd1\u5668\u4f18\u5316\u3001\u5904\u7406\u5668\u91cd\u6392\u5e8f\u7b49\u56e0\u7d20\u4e0d\u4f1a\u5f71\u54cd\u5148\u6267\u884c A \u518d\u6267\u884c B \u7684\u987a\u5e8f\u3002<\/p>\n<h2>\u8bfe\u540e\u601d\u8003<\/h2>\n<p>JMM \u548c\u5185\u5b58\u5c4f\u969c\u6709\u4ec0\u4e48\u5173\u7cfb\uff1fhappens-before \u539f\u5219\u548c\u5185\u5b58\u5c4f\u969c\u6709\u4ec0\u4e48\u5173\u7cfb\uff1f\u5185\u5b58\u5c4f\u969c\u7684\u7c7b\u578b\u53c8\u6709\u54ea\u4e9b\uff1f<\/p>\n<\/li>\n<\/ul>\n<p><a href=\"https:\/\/segmentfault.com\/a\/1190000044649387\">https:\/\/segmentfault.com\/a\/1190000044649387<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5f53\u95ee\u5230 Java \u5185\u5b58\u6a21\u578b\u7684\u65f6\u5019\uff0c\u4e00\u5b9a\u8981\u6ce8\u610f\uff0cJava \u5185\u5b58\u6a21\u578b\uff08Java Memory Model\uff0cJMM\uff09 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[4],"tags":[],"class_list":["post-10008387","post","type-post","status-publish","format-standard","hentry","category-share"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts\/10008387","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=10008387"}],"version-history":[{"count":0,"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts\/10008387\/revisions"}],"wp:attachment":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=10008387"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=10008387"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=10008387"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}