{"id":7933,"date":"2022-10-29T20:28:35","date_gmt":"2022-10-29T12:28:35","guid":{"rendered":"http:\/\/123.57.164.21\/?p=7933"},"modified":"2022-10-29T20:28:35","modified_gmt":"2022-10-29T12:28:35","slug":"38-%e9%ab%98%e9%80%9f%e7%bc%93%e5%ad%98%ef%bc%88%e4%b8%8b%ef%bc%89%ef%bc%9a%e4%bd%a0%e7%a1%ae%e5%ae%9a%e4%bd%a0%e7%9a%84%e6%95%b0%e6%8d%ae%e6%9b%b4%e6%96%b0%e4%ba%86%e4%b9%88%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/92it.top\/?p=7933","title":{"rendered":"38 | \u9ad8\u901f\u7f13\u5b58\uff08\u4e0b\uff09\uff1a\u4f60\u786e\u5b9a\u4f60\u7684\u6570\u636e\u66f4\u65b0\u4e86\u4e48\uff1f"},"content":{"rendered":"\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/123.57.164.21\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-117-1024x730.png\" alt=\"\" class=\"wp-image-7934\" width=\"515\" height=\"366\" srcset=\"https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-117-1024x730.png 1024w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-117-300x214.png 300w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-117-768x548.png 768w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-117-830x592.png 830w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-117-230x164.png 230w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-117-350x250.png 350w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-117-480x342.png 480w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-117.png 1242w\" sizes=\"(max-width: 515px) 100vw, 515px\" \/><\/figure><\/div>\n\n\n\n<p>\u5728\u6211\u5de5\u4f5c\u7684\u5341\u51e0\u5e74\u91cc\uff0c\u5199\u4e86\u5f88\u591a Java \u7684\u7a0b\u5e8f\u3002\u540c\u65f6\uff0c\u6211\u4e5f\u9762\u8bd5\u8fc7\u5927\u91cf\u7684 Java \u5de5\u7a0b\u5e08\u3002\u5bf9\u4e8e\u4e00\u4e9b\u8868\u793a\u81ea\u5df1\u6df1\u5165\u4e86\u89e3\u548c\u64c5\u957f\u591a\u7ebf\u7a0b\u7684\u540c\u5b66\uff0c\u6211\u7ecf\u5e38\u4f1a\u95ee\u8fd9\u6837\u4e00\u4e2a\u9762\u8bd5\u9898\uff1a\u201cvolatile \u8fd9\u4e2a\u5173\u952e\u5b57\u6709\u4ec0\u4e48\u4f5c\u7528\uff1f\u201d\u5982\u679c\u4f60\u6216\u8005\u4f60\u7684\u670b\u53cb\u5199\u8fc7 Java \u7a0b\u5e8f\uff0c\u4e0d\u59a8\u6765\u4e00\u8d77\u8bd5\u7740\u56de\u7b54\u4e00\u4e0b\u8fd9\u4e2a\u95ee\u9898\u3002<\/p>\n\n\n\n<p>\u5c31\u6211\u9762\u8bd5\u8fc7\u7684\u5de5\u7a0b\u5e08\u800c\u8a00\uff0c\u5373\u4f7f\u662f\u5de5\u4f5c\u4e86\u591a\u5e74\u7684 Java \u5de5\u7a0b\u5e08\uff0c\u4e5f\u5f88\u5c11\u6709\u4eba\u80fd\u51c6\u786e\u8bf4\u51fa volatile \u8fd9\u4e2a\u5173\u952e\u5b57\u7684\u542b\u4e49\u3002\u8fd9\u91cc\u9762\u6700\u5e38\u89c1\u7684\u7406\u89e3\u9519\u8bef\u6709\u4e24\u4e2a\uff0c\u4e00\u4e2a\u662f\u628a volatile \u5f53\u6210\u4e00\u79cd\u9501\u673a\u5236\uff0c\u8ba4\u4e3a\u7ed9\u53d8\u91cf\u52a0\u4e0a\u4e86 volatile\uff0c\u5c31\u597d\u50cf\u662f\u7ed9\u51fd\u6570\u52a0\u4e86 sychronized \u5173\u952e\u5b57\u4e00\u6837\uff0c\u4e0d\u540c\u7684\u7ebf\u7a0b\u5bf9\u4e8e\u7279\u5b9a\u53d8\u91cf\u7684\u8bbf\u95ee\u4f1a\u53bb\u52a0\u9501\uff1b\u53e6\u4e00\u4e2a\u662f\u628a volatile \u5f53\u6210\u4e00\u79cd\u539f\u5b50\u5316\u7684\u64cd\u4f5c\u673a\u5236\uff0c\u8ba4\u4e3a\u52a0\u4e86 volatile \u4e4b\u540e\uff0c\u5bf9\u4e8e\u4e00\u4e2a\u53d8\u91cf\u7684\u81ea\u589e\u7684\u64cd\u4f5c\u5c31\u4f1a\u53d8\u6210\u539f\u5b50\u6027\u7684\u4e86\u3002<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">\n\/\/ \u4e00\u79cd\u9519\u8bef\u7684\u7406\u89e3\uff0c\u662f\u628avolatile\u5173\u952e\u8bcd\uff0c\u5f53\u6210\u662f\u4e00\u4e2a\u9501\uff0c\u53ef\u4ee5\u628along\/double\u8fd9\u6837\u7684\u6570\u7684\u64cd\u4f5c\u81ea\u52a8\u52a0\u9501\nprivate volatile long synchronizedValue = 0;\n\n\/\/ \u53e6\u4e00\u79cd\u9519\u8bef\u7684\u7406\u89e3\uff0c\u662f\u628avolatile\u5173\u952e\u8bcd\uff0c\u5f53\u6210\u53ef\u4ee5\u8ba9\u6574\u6570\u81ea\u589e\u7684\u64cd\u4f5c\u4e5f\u53d8\u6210\u539f\u5b50\u6027\u7684\nprivate volatile int atomicInt = 0;\namoticInt++;<\/pre>\n\n\n\n<p>\u4e8b\u5b9e\u4e0a\uff0c\u8fd9\u4e24\u79cd\u7406\u89e3\u90fd\u662f\u5b8c\u5168\u9519\u8bef\u7684\u3002\u5f88\u591a\u5de5\u7a0b\u5e08\u5bb9\u6613\u628a volatile \u5173\u952e\u5b57\uff0c\u5f53\u6210\u548c\u9501\u6216\u8005\u6570\u636e\u6570\u636e\u539f\u5b50\u6027\u76f8\u5173\u7684\u77e5\u8bc6\u70b9\u3002\u800c\u5b9e\u9645\u4e0a\uff0cvolatile \u5173\u952e\u5b57\u7684\u6700\u6838\u5fc3\u77e5\u8bc6\u70b9\uff0c\u8981\u5173\u7cfb\u5230 Java \u5185\u5b58\u6a21\u578b\uff08JMM\uff0cJava Memory Model\uff09\u4e0a\u3002<\/p>\n\n\n\n<p>\u867d\u7136 JMM \u53ea\u662f Java \u865a\u62df\u673a\u8fd9\u4e2a\u8fdb\u7a0b\u7ea7\u865a\u62df\u673a\u91cc\u7684\u4e00\u4e2a\u5185\u5b58\u6a21\u578b\uff0c\u4f46\u662f\u8fd9\u4e2a\u5185\u5b58\u6a21\u578b\uff0c\u548c\u8ba1\u7b97\u673a\u7ec4\u6210\u91cc\u7684 CPU\u3001\u9ad8\u901f\u7f13\u5b58\u548c\u4e3b\u5185\u5b58\u7ec4\u5408\u5728\u4e00\u8d77\u7684\u786c\u4ef6\u4f53\u7cfb\u975e\u5e38\u76f8\u4f3c\u3002\u7406\u89e3\u4e86 JMM\uff0c\u53ef\u4ee5\u8ba9\u4f60\u5f88\u5bb9\u6613\u7406\u89e3\u8ba1\u7b97\u673a\u7ec4\u6210\u91cc CPU\u3001\u9ad8\u901f\u7f13\u5b58\u548c\u4e3b\u5185\u5b58\u4e4b\u95f4\u7684\u5173\u7cfb\u3002<\/p>\n\n\n\n<p><strong>\u201c\u9690\u8eab\u201d\u7684\u53d8\u91cf<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator\"\/>\n\n\n\n<p>\u6211\u4eec\u5148\u6765\u4e00\u8d77\u770b\u4e00\u6bb5 Java \u7a0b\u5e8f\u3002\u8fd9\u662f\u4e00\u6bb5\u7ecf\u5178\u7684 volatile \u4ee3\u7801\uff0c\u6765\u81ea\u77e5\u540d\u7684 Java \u5f00\u53d1\u8005\u7f51\u7ad9dzone.com\uff0c\u540e\u7eed\u6211\u4eec\u4f1a\u4fee\u6539\u8fd9\u6bb5\u4ee3\u7801\u6765\u8fdb\u884c\u5404\u79cd\u5c0f\u5b9e\u9a8c\u3002<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\npublic class VolatileTest {\n    private static volatile int COUNTER = 0;\n\n    public static void main(String[] args) {\n        new ChangeListener().start();\n        new ChangeMaker().start();\n    }\n\n    static class ChangeListener extends Thread {\n        @Override\n        public void run() {\n            int threadValue = COUNTER;\n            while ( threadValue &lt; 5){\n                if( threadValue!= COUNTER){\n                    System.out.println(\"Got Change for COUNTER : \" + COUNTER + \"\");\n                    threadValue= COUNTER;\n                }\n            }\n        }\n    }\n\n    static class ChangeMaker extends Thread{\n        @Override\n        public void run() {\n            int threadValue = COUNTER;\n            while (COUNTER &lt;5){\n                System.out.println(\"Incrementing COUNTER to : \" + (threadValue+1) + \"\");\n                COUNTER = ++threadValue;\n                try {\n                    Thread.sleep(500);\n                } catch (InterruptedException e) { e.printStackTrace(); }\n            }\n        }\n    }\n}<\/pre>\n\n\n\n<p>\u6211\u4eec\u5148\u6765\u770b\u770b\u8fd9\u4e2a\u7a0b\u5e8f\u505a\u4e86\u4ec0\u4e48\u3002\u5728\u8fd9\u4e2a\u7a0b\u5e8f\u91cc\uff0c\u6211\u4eec\u5148\u5b9a\u4e49\u4e86\u4e00\u4e2a volatile \u7684 int \u7c7b\u578b\u7684\u53d8\u91cf\uff0cCOUNTER\u3002<\/p>\n\n\n\n<p>\u7136\u540e\uff0c\u6211\u4eec\u5206\u522b\u542f\u52a8\u4e86\u4e24\u4e2a\u5355\u72ec\u7684\u7ebf\u7a0b\uff0c\u4e00\u4e2a\u7ebf\u7a0b\u6211\u4eec\u53eb ChangeListener\u3002\u53e6\u4e00\u4e2a\u7ebf\u7a0b\uff0c\u6211\u4eec\u53eb ChangeMaker\u3002<\/p>\n\n\n\n<p>ChangeListener \u8fd9\u4e2a\u7ebf\u7a0b\u8fd0\u884c\u7684\u4efb\u52a1\u5f88\u7b80\u5355\u3002\u5b83\u5148\u53d6\u5230 COUNTER \u5f53\u524d\u7684\u503c\uff0c\u7136\u540e\u4e00\u76f4\u76d1\u542c\u7740\u8fd9\u4e2a COUNTER \u7684\u503c\u3002\u4e00\u65e6 COUNTER \u7684\u503c\u53d1\u751f\u4e86\u53d8\u5316\uff0c\u5c31\u628a\u65b0\u7684\u503c\u901a\u8fc7 println \u6253\u5370\u51fa\u6765\u3002\u76f4\u5230 COUNTER \u7684\u503c\u8fbe\u5230 5 \u4e3a\u6b62\u3002\u8fd9\u4e2a\u76d1\u542c\u7684\u8fc7\u7a0b\uff0c\u901a\u8fc7\u4e00\u4e2a\u6c38\u4e0d\u505c\u6b47\u7684 while \u5faa\u73af\u7684\u5fd9\u7b49\u5f85\u6765\u5b9e\u73b0\u3002<\/p>\n\n\n\n<p>ChangeMaker \u8fd9\u4e2a\u7ebf\u7a0b\u8fd0\u884c\u7684\u4efb\u52a1\u540c\u6837\u5f88\u7b80\u5355\u3002\u5b83\u540c\u6837\u662f\u53d6\u5230 COUNTER \u7684\u503c\uff0c\u5728 COUNTER \u5c0f\u4e8e 5 \u7684\u65f6\u5019\uff0c\u6bcf\u9694 500 \u6beb\u79d2\uff0c\u5c31\u8ba9 COUNTER \u81ea\u589e 1\u3002\u5728\u81ea\u589e\u4e4b\u524d\uff0c\u901a\u8fc7 println \u65b9\u6cd5\u628a\u81ea\u589e\u540e\u7684\u503c\u6253\u5370\u51fa\u6765\u3002<\/p>\n\n\n\n<p>\u6700\u540e\uff0c\u5728 main \u51fd\u6570\u91cc\uff0c\u6211\u4eec\u5206\u522b\u542f\u52a8\u8fd9\u4e24\u4e2a\u7ebf\u7a0b\uff0c\u6765\u770b\u4e00\u770b\u8fd9\u4e2a\u7a0b\u5e8f\u7684\u6267\u884c\u60c5\u51b5\u3002\u7a0b\u5e8f\u7684\u8f93\u51fa\u7ed3\u679c\u5e76\u4e0d\u8ba9\u4eba\u610f\u5916\u3002ChangeMaker \u51fd\u6570\u4f1a\u4e00\u6b21\u4e00\u6b21\u5c06 COUNTER \u4ece 0 \u589e\u52a0\u5230 5\u3002\u56e0\u4e3a\u8fd9\u4e2a\u81ea\u589e\u662f\u6bcf 500 \u6beb\u79d2\u4e00\u6b21\uff0c\u800c ChangeListener \u53bb\u76d1\u542c COUNTER \u662f\u5fd9\u7b49\u5f85\u7684\uff0c\u6240\u4ee5\u6bcf\u4e00\u6b21\u81ea\u589e\u90fd\u4f1a\u88ab ChangeListener \u76d1\u542c\u5230\uff0c\u7136\u540e\u5bf9\u5e94\u7684\u7ed3\u679c\u5c31\u4f1a\u88ab\u6253\u5370\u51fa\u6765\u3002<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/123.57.164.21\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-118.png\" alt=\"\" class=\"wp-image-7935\" width=\"268\" height=\"210\" srcset=\"https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-118.png 572w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-118-300x235.png 300w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-118-230x180.png 230w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-118-350x274.png 350w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-118-480x376.png 480w\" sizes=\"(max-width: 268px) 100vw, 268px\" \/><\/figure><\/div>\n\n\n\n<p>\u8fd9\u4e2a\u65f6\u5019\uff0c\u6211\u4eec\u5c31\u53ef\u4ee5\u6765\u505a\u4e00\u4e2a\u5f88\u6709\u610f\u601d\u7684\u5b9e\u9a8c\u3002\u5982\u679c\u6211\u4eec\u628a\u4e0a\u9762\u7684\u7a0b\u5e8f\u5c0f\u5c0f\u5730\u4fee\u6539\u4e00\u884c\u4ee3\u7801\uff0c\u628a\u6211\u4eec\u5b9a\u4e49 COUNTER \u8fd9\u4e2a\u53d8\u91cf\u7684\u65f6\u5019\uff0c\u8bbe\u7f6e\u7684 volatile \u5173\u952e\u5b57\u7ed9\u53bb\u6389\uff0c\u4f1a\u53d1\u751f\u4ec0\u4e48\u4e8b\u60c5\u5462\uff1f\u4f60\u53ef\u4ee5\u81ea\u5df1\u5148\u8bd5\u4e00\u8bd5\uff0c\u770b\u7ed3\u679c\u662f\u5426\u4f1a\u8ba9\u4f60\u5927\u5403\u4e00\u60ca\u3002<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">private static int COUNTER = 0;<\/pre>\n\n\n\n<p>\u6ca1\u9519\uff0c\u4f60\u4f1a\u53d1\u73b0\uff0c\u6211\u4eec\u7684 ChangeMaker \u8fd8\u662f\u80fd\u6b63\u5e38\u5de5\u4f5c\u7684\uff0c\u6bcf\u9694 500ms \u4ecd\u7136\u80fd\u591f\u5bf9 COUNTER \u81ea\u589e 1\u3002\u4f46\u662f\uff0c\u5947\u602a\u7684\u4e8b\u60c5\u5728 ChangeListener \u4e0a\u53d1\u751f\u4e86\uff0c\u6211\u4eec\u7684 ChangeListener \u4e0d\u518d\u5de5\u4f5c\u4e86\u3002\u5728 ChangeListener \u773c\u91cc\uff0c\u5b83\u4f3c\u4e4e\u4e00\u76f4\u89c9\u5f97 COUNTER \u7684\u503c\u8fd8\u662f\u4e00\u5f00\u59cb\u7684 0\u3002\u4f3c\u4e4e COUNTER \u7684\u53d8\u5316\uff0c\u5bf9\u4e8e\u6211\u4eec\u7684 ChangeListener \u5f7b\u5e95\u201c\u9690\u8eab\u201d\u4e86\u3002<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/123.57.164.21\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-119.png\" alt=\"\" class=\"wp-image-7936\" width=\"324\" height=\"163\" srcset=\"https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-119.png 616w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-119-300x151.png 300w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-119-230x116.png 230w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-119-350x176.png 350w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-119-480x242.png 480w\" sizes=\"(max-width: 324px) 100vw, 324px\" \/><\/figure><\/div>\n\n\n\n<p>\u8fd9\u4e2a\u6709\u610f\u601d\u7684\u5c0f\u7a0b\u5e8f\u8fd8\u6ca1\u6709\u7ed3\u675f\uff0c\u6211\u4eec\u53ef\u4ee5\u518d\u5bf9\u7a0b\u5e8f\u505a\u4e00\u4e9b\u5c0f\u5c0f\u7684\u4fee\u6539\u3002\u6211\u4eec\u4e0d\u518d\u8ba9 ChangeListener \u8fdb\u884c\u5b8c\u5168\u7684\u5fd9\u7b49\u5f85\uff0c\u800c\u662f\u5728 while \u5faa\u73af\u91cc\u9762\uff0c\u5c0f\u5c0f\u5730\u7b49\u5f85\u4e0a 5 \u6beb\u79d2\uff0c\u770b\u770b\u4f1a\u53d1\u751f\u4ec0\u4e48\u60c5\u51b5\u3002<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\nstatic class ChangeListener extends Thread {\n    @Override\n    public void run() {\n        int threadValue = COUNTER;\n        while ( threadValue &lt; 5){\n            if( threadValue!= COUNTER){\n                System.out.println(\"Sleep 5ms, Got Change for COUNTER : \" + COUNTER + \"\");\n                threadValue= COUNTER;\n            }\n            try {\n                Thread.sleep(5);\n            } catch (InterruptedException e) { e.printStackTrace(); }\n        }\n    }\n}<\/pre>\n\n\n\n<p>\u597d\u4e86\uff0c\u4e0d\u77e5\u9053\u4f60\u6709\u6ca1\u6709\u81ea\u5df1\u52a8\u624b\u8bd5\u4e00\u8bd5\u5462\uff1f\u53c8\u4e00\u4e2a\u4ee4\u4eba\u60ca\u5947\u7684\u73b0\u8c61\u8981\u53d1\u751f\u4e86\u3002\u867d\u7136\u6211\u4eec\u7684 COUNTER \u53d8\u91cf\uff0c\u4ecd\u7136\u6ca1\u6709\u8bbe\u7f6e volatile \u8fd9\u4e2a\u5173\u952e\u5b57\uff0c\u4f46\u662f\u6211\u4eec\u7684 ChangeListener \u4f3c\u4e4e\u201c\u7761\u9192\u4e86\u201d\u3002\u5728\u901a\u8fc7 Thread.sleep(5) \u5728\u6bcf\u4e2a\u5faa\u73af\u91cc\u201c\u7761\u4e0a\u201c5 \u6beb\u79d2\u4e4b\u540e\uff0cChangeListener \u53c8\u80fd\u591f\u6b63\u5e38\u53d6\u5230 COUNTER \u7684\u503c\u4e86\u3002<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/123.57.164.21\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-120.png\" alt=\"\" class=\"wp-image-7938\" width=\"334\" height=\"212\" srcset=\"https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-120.png 690w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-120-300x190.png 300w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-120-230x146.png 230w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-120-350x222.png 350w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-120-480x305.png 480w\" sizes=\"(max-width: 334px) 100vw, 334px\" \/><\/figure><\/div>\n\n\n\n<p>\u8fd9\u4e9b\u6709\u610f\u601d\u7684\u73b0\u8c61\uff0c\u5176\u5b9e\u6765\u81ea\u4e8e\u6211\u4eec\u7684 Java \u5185\u5b58\u6a21\u578b\u4ee5\u53ca\u5173\u952e\u5b57 volatile \u7684\u542b\u4e49\u3002\u90a3 volatile \u5173\u952e\u5b57\u7a76\u7adf\u4ee3\u8868\u4ec0\u4e48\u542b\u4e49\u5462\uff1f\u5b83\u4f1a\u786e\u4fdd\u6211\u4eec\u5bf9\u4e8e\u8fd9\u4e2a\u53d8\u91cf\u7684\u8bfb\u53d6\u548c\u5199\u5165\uff0c\u90fd\u4e00\u5b9a\u4f1a\u540c\u6b65\u5230\u4e3b\u5185\u5b58\u91cc\uff0c\u800c\u4e0d\u662f\u4ece Cache \u91cc\u9762\u8bfb\u53d6\u3002\u8be5\u600e\u4e48\u7406\u89e3\u8fd9\u4e2a\u89e3\u91ca\u5462\uff1f\u6211\u4eec\u901a\u8fc7\u521a\u624d\u7684\u4f8b\u5b50\u6765\u8fdb\u884c\u5206\u6790\u3002<\/p>\n\n\n\n<p>\u521a\u521a\u7b2c\u4e00\u4e2a\u4f7f\u7528\u4e86 volatile \u5173\u952e\u5b57\u7684\u4f8b\u5b50\u91cc\uff0c\u56e0\u4e3a\u6240\u6709\u6570\u636e\u7684\u8bfb\u548c\u5199\u90fd\u6765\u81ea\u4e3b\u5185\u5b58\u3002\u90a3\u4e48\u81ea\u7136\u5730\uff0c\u6211\u4eec\u7684 ChangeMaker \u548c ChangeListener \u4e4b\u95f4\uff0c\u770b\u5230\u7684 COUNTER \u503c\u5c31\u662f\u4e00\u6837\u7684\u3002<\/p>\n\n\n\n<p>\u5230\u4e86\u7b2c\u4e8c\u6bb5\u8fdb\u884c\u5c0f\u5c0f\u4fee\u6539\u7684\u65f6\u5019\uff0c\u6211\u4eec\u53bb\u6389\u4e86 volatile \u5173\u952e\u5b57\u3002\u8fd9\u4e2a\u65f6\u5019\uff0cChangeListener \u53c8\u662f\u4e00\u4e2a\u5fd9\u7b49\u5f85\u7684\u5faa\u73af\uff0c\u5b83\u5c1d\u8bd5\u4e0d\u505c\u5730\u83b7\u53d6 COUNTER \u7684\u503c\uff0c\u8fd9\u6837\u5c31\u4f1a\u4ece\u5f53\u524d\u7ebf\u7a0b\u7684\u201cCache\u201d\u91cc\u9762\u83b7\u53d6\u3002\u4e8e\u662f\uff0c\u8fd9\u4e2a\u7ebf\u7a0b\u5c31\u6ca1\u6709\u65f6\u95f4\u4ece\u4e3b\u5185\u5b58\u91cc\u9762\u540c\u6b65\u66f4\u65b0\u540e\u7684 COUNTER \u503c\u3002\u8fd9\u6837\uff0c\u5b83\u5c31\u4e00\u76f4\u5361\u6b7b\u5728 COUNTER=0 \u7684\u6b7b\u5faa\u73af\u4e0a\u4e86\u3002<\/p>\n\n\n\n<p>\u800c\u5230\u4e86\u6211\u4eec\u518d\u6b21\u4fee\u6539\u7684\u7b2c\u4e09\u6bb5\u4ee3\u7801\u91cc\u9762\uff0c\u867d\u7136\u8fd8\u662f\u6ca1\u6709\u4f7f\u7528 volatile \u5173\u952e\u5b57\uff0c\u4f46\u662f\u77ed\u77ed 5ms \u7684 Thead.Sleep \u7ed9\u4e86\u8fd9\u4e2a\u7ebf\u7a0b\u5598\u606f\u4e4b\u673a\u3002\u65e2\u7136\u8fd9\u4e2a\u7ebf\u7a0b\u6ca1\u6709\u8fd9\u4e48\u5fd9\u4e86\uff0c\u5b83\u4e5f\u5c31\u6709\u673a\u4f1a\u628a\u6700\u65b0\u7684\u6570\u636e\u4ece\u4e3b\u5185\u5b58\u540c\u6b65\u5230\u81ea\u5df1\u7684\u9ad8\u901f\u7f13\u5b58\u91cc\u9762\u4e86\u3002\u4e8e\u662f\uff0cChangeListener \u5728\u4e0b\u4e00\u6b21\u67e5\u770b COUNTER \u503c\u7684\u65f6\u5019\uff0c\u5c31\u80fd\u770b\u5230 ChangeMaker \u9020\u6210\u7684\u53d8\u5316\u4e86\u3002<\/p>\n\n\n\n<p>\u867d\u7136 Java \u5185\u5b58\u6a21\u578b\u662f\u4e00\u4e2a\u9694\u79bb\u4e86\u786c\u4ef6\u5b9e\u73b0\u7684\u865a\u62df\u673a\u5185\u7684\u62bd\u8c61\u6a21\u578b\uff0c\u4f46\u662f\u5b83\u7ed9\u4e86\u6211\u4eec\u4e00\u4e2a\u5f88\u597d\u7684\u201c\u7f13\u5b58\u540c\u6b65\u201d\u95ee\u9898\u7684\u793a\u4f8b\u3002\u4e5f\u5c31\u662f\u8bf4\uff0c\u5982\u679c\u6211\u4eec\u7684\u6570\u636e\uff0c\u5728\u4e0d\u540c\u7684\u7ebf\u7a0b\u6216\u8005 CPU \u6838\u91cc\u9762\u53bb\u66f4\u65b0\uff0c\u56e0\u4e3a\u4e0d\u540c\u7684\u7ebf\u7a0b\u6216 CPU \u6838\u6709\u7740\u81ea\u5df1\u5404\u81ea\u7684\u7f13\u5b58\uff0c\u5f88\u6709\u53ef\u80fd\u5728 A \u7ebf\u7a0b\u7684\u66f4\u65b0\uff0c\u5230 B \u7ebf\u7a0b\u91cc\u9762\u662f\u770b\u4e0d\u89c1\u7684\u3002<\/p>\n\n\n\n<p><strong>CPU \u9ad8\u901f\u7f13\u5b58\u7684\u5199\u5165<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator\"\/>\n\n\n\n<p>\u4e8b\u5b9e\u4e0a\uff0c\u6211\u4eec\u53ef\u4ee5\u628a Java \u5185\u5b58\u6a21\u578b\u548c\u8ba1\u7b97\u673a\u7ec4\u6210\u91cc\u7684 CPU \u7ed3\u6784\u5bf9\u7167\u8d77\u6765\u770b\u3002<\/p>\n\n\n\n<p>\u6211\u4eec\u73b0\u5728\u7528\u7684 Intel CPU\uff0c\u901a\u5e38\u90fd\u662f\u591a\u6838\u7684\u7684\u3002\u6bcf\u4e00\u4e2a CPU \u6838\u91cc\u9762\uff0c\u90fd\u6709\u72ec\u7acb\u5c5e\u4e8e\u81ea\u5df1\u7684 L1\u3001L2 \u7684 Cache\uff0c\u7136\u540e\u518d\u6709\u591a\u4e2a CPU \u6838\u5171\u7528\u7684 L3 \u7684 Cache\u3001\u4e3b\u5185\u5b58\u3002<\/p>\n\n\n\n<p>\u56e0\u4e3a CPU Cache \u7684\u8bbf\u95ee\u901f\u5ea6\u8981\u6bd4\u4e3b\u5185\u5b58\u5feb\u5f88\u591a\uff0c\u800c\u5728 CPU Cache \u91cc\u9762\uff0cL1\/L2 \u7684 Cache \u4e5f\u8981\u6bd4 L3 \u7684 Cache \u5feb\u3002\u6240\u4ee5\uff0c\u4e0a\u4e00\u8bb2\u6211\u4eec\u53ef\u4ee5\u770b\u5230\uff0cCPU \u59cb\u7ec8\u90fd\u662f\u5c3d\u53ef\u80fd\u5730\u4ece CPU Cache \u4e2d\u53bb\u83b7\u53d6\u6570\u636e\uff0c\u800c\u4e0d\u662f\u6bcf\u4e00\u6b21\u90fd\u8981\u4ece\u4e3b\u5185\u5b58\u91cc\u9762\u53bb\u8bfb\u53d6\u6570\u636e\u3002<\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/123.57.164.21\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-121-1024x744.png\" alt=\"\" class=\"wp-image-7939\" width=\"473\" height=\"343\" srcset=\"https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-121-1024x744.png 1024w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-121-300x218.png 300w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-121-768x558.png 768w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-121-830x603.png 830w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-121-550x400.png 550w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-121-230x167.png 230w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-121-350x254.png 350w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-121-480x349.png 480w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-121.png 1084w\" sizes=\"(max-width: 473px) 100vw, 473px\" \/><\/figure><\/div>\n\n\n\n<p>\u8fd9\u4e2a\u5c42\u7ea7\u7ed3\u6784\uff0c\u5c31\u597d\u50cf\u6211\u4eec\u5728 Java \u5185\u5b58\u6a21\u578b\u91cc\u9762\uff0c\u6bcf\u4e00\u4e2a\u7ebf\u7a0b\u90fd\u6709\u5c5e\u4e8e\u81ea\u5df1\u7684\u7ebf\u7a0b\u6808\u3002\u7ebf\u7a0b\u5728\u8bfb\u53d6 COUNTER \u7684\u6570\u636e\u7684\u65f6\u5019\uff0c\u5176\u5b9e\u662f\u4ece\u672c\u5730\u7684\u7ebf\u7a0b\u6808\u7684 Cache \u526f\u672c\u91cc\u9762\u8bfb\u53d6\u6570\u636e\uff0c\u800c\u4e0d\u662f\u4ece\u4e3b\u5185\u5b58\u91cc\u9762\u8bfb\u53d6\u6570\u636e\u3002\u5982\u679c\u6211\u4eec\u5bf9\u4e8e\u6570\u636e\u4ec5\u4ec5\u53ea\u662f\u8bfb\uff0c\u95ee\u9898\u8fd8\u4e0d\u5927\u3002\u6211\u4eec\u5728\u4e0a\u4e00\u8bb2\u91cc\uff0c\u5df2\u7ecf\u770b\u5230 Cache Line \u7684\u7ec4\u6210\uff0c\u4ee5\u53ca\u5982\u4f55\u4ece\u5185\u5b58\u91cc\u9762\u628a\u5bf9\u5e94\u7684\u6570\u636e\u52a0\u8f7d\u5230 Cache \u91cc\u3002<\/p>\n\n\n\n<p>\u4f46\u662f\uff0c\u5bf9\u4e8e\u6570\u636e\uff0c\u6211\u4eec\u4e0d\u5149\u8981\u8bfb\uff0c\u8fd8\u8981\u53bb\u5199\u5165\u4fee\u6539\u3002\u8fd9\u4e2a\u65f6\u5019\uff0c\u6709\u4e24\u4e2a\u95ee\u9898\u6765\u4e86\u3002<\/p>\n\n\n\n<p>\u7b2c\u4e00\u4e2a\u95ee\u9898\u662f\uff0c\u5199\u5165 Cache \u7684\u6027\u80fd\u4e5f\u6bd4\u5199\u5165\u4e3b\u5185\u5b58\u8981\u5feb\uff0c\u90a3\u6211\u4eec\u5199\u5165\u7684\u6570\u636e\uff0c\u5230\u5e95\u5e94\u8be5\u5199\u5230 Cache \u91cc\u8fd8\u662f\u4e3b\u5185\u5b58\u5462\uff1f\u5982\u679c\u6211\u4eec\u76f4\u63a5\u5199\u5165\u5230\u4e3b\u5185\u5b58\u91cc\uff0cCache 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https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-122-350x594.png 350w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-122-480x814.png 480w, https:\/\/92it.top\/wp-content\/uploads\/2022\/10\/\u56fe\u7247-122.png 822w\" sizes=\"(max-width: 271px) 100vw, 271px\" \/><\/figure><\/div>\n\n\n\n<p>\u6700\u7b80\u5355\u7684\u4e00\u79cd\u5199\u5165\u7b56\u7565\uff0c\u53eb\u4f5c\u5199\u76f4\u8fbe\uff08Write-Through\uff09\u3002\u5728\u8fd9\u4e2a\u7b56\u7565\u91cc\uff0c\u6bcf\u4e00\u6b21\u6570\u636e\u90fd\u8981\u5199\u5165\u5230\u4e3b\u5185\u5b58\u91cc\u9762\u3002\u5728\u5199\u76f4\u8fbe\u7684\u7b56\u7565\u91cc\u9762\uff0c\u5199\u5165\u524d\uff0c\u6211\u4eec\u4f1a\u5148\u53bb\u5224\u65ad\u6570\u636e\u662f\u5426\u5df2\u7ecf\u5728 Cache \u91cc\u9762\u4e86\u3002\u5982\u679c\u6570\u636e\u5df2\u7ecf\u5728 Cache \u91cc\u9762\u4e86\uff0c\u6211\u4eec\u5148\u628a\u6570\u636e\u5199\u5165\u66f4\u65b0\u5230 Cache 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