{"id":10008192,"date":"2023-08-29T23:01:33","date_gmt":"2023-08-29T15:01:33","guid":{"rendered":"https:\/\/blog.itmax.cn\/?p=10008192"},"modified":"2023-08-29T23:01:33","modified_gmt":"2023-08-29T15:01:33","slug":"%e9%9d%a2%e8%af%95%e5%ae%98%ef%bc%9asynchronized-%e8%83%bd%e4%b8%8d%e8%83%bd%e7%a6%81%e6%ad%a2%e6%8c%87%e4%bb%a4%e9%87%8d%e6%8e%92%e5%ba%8f%ef%bc%9f%e5%a4%a7%e9%83%a8%e5%88%86%e4%ba%ba%e9%83%bd","status":"publish","type":"post","link":"https:\/\/itmax.cn\/?p=10008192","title":{"rendered":"\u9762\u8bd5\u5b98\uff1asynchronized \u80fd\u4e0d\u80fd\u7981\u6b62\u6307\u4ee4\u91cd\u6392\u5e8f\uff1f\u5927\u90e8\u5206\u4eba\u90fd\u4f1a\u7b54\u9519\uff01"},"content":{"rendered":"<h2>\u6307\u4ee4\u91cd\u6392\u5e8f<\/h2>\n<h3>1\u3001\u95ee\u9898\u63cf\u8ff0<\/h3>\n<p>\u9996\u5148\u4e00\u5b9a\u8981\u660e\u786e\uff1a\u6307\u4ee4\u91cd\u6392\u5e8f\u548c\u6709\u5e8f\u6027\u662f\u4e0d\u4e00\u6837\u7684\u3002\u8fd9\u4e00\u70b9\u975e\u5e38\u91cd\u8981\u3002<\/p>\n<p>\u6211\u4eec\u7ecf\u5e38\u90fd\u4f1a\u8fd9\u4e48\u8bf4\uff1a<\/p>\n<ul>\n<li>volatile\u80fd\u4fdd\u8bc1\u5185\u5b58\u53ef\u89c1\u6027\u3001\u7981\u6b62\u6307\u4ee4\u91cd\u6392\u5e8f\u4f46\u662f\u4e0d\u80fd\u4fdd\u8bc1\u539f\u5b50\u6027\u3002<\/li>\n<li>synchronized\u80fd\u4fdd\u8bc1\u539f\u5b50\u6027\u3001\u53ef\u89c1\u6027\u548c\u6709\u5e8f\u6027\u3002<\/li>\n<\/ul>\n<blockquote><p>\u6ce8\u610f\uff1a\u8fd9\u91cc\u7684\u6709\u5e8f\u6027\u5e76\u4e0d\u662f\u4ee3\u8868\u80fd\u7981\u6b62\u6307\u4ee4\u91cd\u6392\u5e8f\u3002<\/p><\/blockquote>\n<p>\u4e3e\u4e2a\u4f8b\u5b50\uff1a<\/p>\n<p>\u5728\u53cc\u91cd\u68c0\u67e5\u7684\u5355\u4f8b\u6a21\u5f0f\u4e2d\uff0c\u65e2\u7136\u5df2\u7ecf\u52a0\u4e86synchronized\u4e3a\u4ec0\u4e48\u8fd8\u9700\u8981volatile\u53bb\u4fee\u9970\u53d8\u91cf\u5462\uff1f\u5982\u679csynchronized\u80fd\u7981\u6b62\u6307\u4ee4\u91cd\u6392\uff0c\u90a3\u4e48\u5b8c\u5168\u53ef\u4ee5\u4e0d\u7528\u8981volatile\u3002<\/p>\n<p>\u63a8\u8350\u4e00\u4e2a\u5f00\u6e90\u514d\u8d39\u7684 Spring Boot \u5b9e\u6218\u9879\u76ee\uff1a<\/p>\n<blockquote><p><a target=\"_blank\" href=\"https:\/\/link.segmentfault.com\/?enc=Lffz3Awwz7%2F8xXlW%2FiNUqw%3D%3D.VRJxBcy8jnz3KuKERC4wfQqzTs4SQRX%2FHZWW6H2b0AbEuzfVSorxJG4kHsfhvvafzwTBsrfYQYYMGhQNqMqKcQ%3D%3D\" rel=\"noopener noreferrer\">https:\/\/github.com\/javastacks\/spring-boot-best-practice<\/a><\/p><\/blockquote>\n<h3>2\u3001DCL\u4ee3\u7801\u5b57\u8282\u7801\u5206\u6790\u6307\u4ee4\u91cd\u6392\u5e8f\u95ee\u9898<\/h3>\n<p>\u9996\u5148\u9700\u8981\u77e5\u9053\u7684\u77e5\u8bc6\u70b9\uff1aObject obj = new Object();\u8fd9\u53e5\u4ee3\u7801\u5e76\u4e0d\u662f\u4e00\u4e2a\u539f\u5b50\u64cd\u4f5c\uff0c\u4ed6\u5206\u4e3a\u4e09\u6b65\uff1a<\/p>\n<ul>\n<li>\u5728\u5185\u5b58\u7533\u8bf7\u4e00\u7247\u7a7a\u95f4\uff0cnew \u51fa\u4e00\u4e2a\u5bf9\u8c61<\/li>\n<li>\u8c03\u7528new\u51fa\u7684\u8fd9\u4e2a\u5bf9\u8c61\u7684\u6784\u9020\u65b9\u6cd5<\/li>\n<li>\u5c06\u8fd9\u4e2a\u5bf9\u8c61\u7684\u5f15\u7528\u8d4b\u503c\u7ed9obj<\/li>\n<\/ul>\n<h5>a)\u3001DCL\u53cc\u91cd\u68c0\u67e5\u4ee3\u7801<\/h5>\n<pre><code>public class MySingleton {\n\n    private static MySingleton INSTANCE;\n\n    private MySingleton() {\n    }\n\n    public static MySingleton getInstance() {\n        if (INSTANCE == null) {\n            synchronized (MySingleton.class) {\n                if (INSTANCE == null) {\n                    INSTANCE = new MySingleton();\n                }\n            }\n        }\n        return INSTANCE;\n    }\n}<\/code><\/pre>\n<h5>b)\u3001\u5b57\u8282\u7801\u5982\u4e0b<\/h5>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"723\" height=\"269\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/bVc9sCL\" alt=\"\" title=\"\"><\/p>\n<p>\u4ece\u5b57\u8282\u7801\u4e2d\u53ef\u4ee5\u770b\u5230\uff0c<code>new MySingleton();<\/code>\u8fd9\u53e5\u4ee3\u7801\u5bf9\u5e94\u4e8617\u300120\u300121\u300124\u8fd9\u56db\u884c\u5b57\u8282\u7801\uff0820\u884c\u662f\u4e00\u4e2a\u5f15\u7528\u7684\u62f7\u8d1d\uff0c\u53ef\u4ee5\u5ffd\u7565\uff09\u3002<\/p>\n<ul>\n<li>\u9996\u5148\u572817\u884c\u5728\u5185\u5b58\u4e2d\u5f00\u8f9f\u4e00\u5757\u7a7a\u95f4\u521b\u5efa\u4e00\u4e2aMySingleton\u5bf9\u8c61\u3002<\/li>\n<li>\u7136\u540e\u572821\u884c\u8c03\u7528\u8be5\u5bf9\u8c61\u7684\u6784\u9020\u65b9\u6cd5\u3002<\/li>\n<li>\u7136\u540e\u572824\u884c\u5c06\u8be5\u5bf9\u8c61\u7684\u5f15\u7528\u8d4b\u503c\u7ed9\u9759\u6001\u53d8\u91cfINSTANCE\u3002<\/li>\n<\/ul>\n<p>\u4ee5\u4e0a\u662f\u6211\u4eec\u671f\u671b\u7684\u6267\u884c\u987a\u5e8f\uff0c\u6211\u4eec\u5e0c\u671b\u6bcf\u4e2a\u7ebf\u7a0b\u90fd\u6309\u7167\u8be5\u987a\u5e8f\u53bb\u6267\u884c\u6307\u4ee4\uff08\u8fd9\u5c31\u662f\u7981\u6b62\u6307\u4ee4\u91cd\u6392\u5e8f\uff09\u3002\u4f46\u662f\u7531\u4e8e\u8ba1\u7b97\u673a\u4e3a\u4e86\u63d0\u9ad8\u8fd0\u884c\u6548\u7387\uff0c\u4f1a\u5c06\u6211\u4eec\u7684\u6307\u4ee4\u987a\u5e8f\u8fdb\u884c\u4f18\u5316\u91cd\u6392\uff08\u6bd4\u5982\u4e0a\u9762\u7684\u987a\u5e8f\u53ef\u80fd\u4f1a\u4f18\u5316\u91cd\u6392\u4e3a\uff1a17\u300124\u300121\uff09<\/p>\n<p><strong>\u6307\u4ee4\u91cd\u6392\u5e8f\u5e26\u6765\u7684\u95ee\u9898<\/strong><\/p>\n<ul>\n<li>\u6211\u4eec\u7684\u8ba1\u7b97\u673a\u4e3a\u4e86\u63d0\u5347\u6548\u7387\uff0c\u4f1a\u5c06\u6211\u4eec\u7684\u4ee3\u7801\u987a\u5e8f\u505a\u4e00\u4e9b\u4f18\u5316\uff0c\u6bd4\u5982\u5728t1\u7ebf\u7a0b\u4e2d\u7684\u6267\u884c\u987a\u5e8f\u662f 17\u300124\u300121\uff0c\u5728t2\u7ebf\u7a0b\u4e2d\u6267\u884c\u7684\u987a\u5e8f\u662f17\u300121\u300124 \uff08\u5728\u5355\u4e2a\u7ebf\u7a0b\u4e2d\u4e0d\u7ba1\u662f\u90a3\u79cd\u6267\u884c\u987a\u5e8f\u90fd\u4e0d\u4f1a\u6709\u95ee\u9898\uff09\u3002<\/li>\n<li>\u5f53t1\u7ebf\u7a0b\u83b7\u53d6\u5230\u9501\u6267\u884c\u5bf9\u8c61\u521b\u5efa\u7684\u65f6\u5019\uff0c\u5148\u6267\u884c\u4e8624\u884c\uff0c\u5c06\u8be5\u5bf9\u8c61\u7684\u5f15\u7528\u8d4b\u503c\u7ed9\u4e86\u9759\u6001\u53d8\u91cfINSTANCE\uff08\u6b64\u65f6\u5bf9\u8c61\u8fd8\u6ca1\u8c03\u7528\u6784\u9020\u65b9\u6cd5\uff0c\u8be5\u5bf9\u8c61\u8fd8\u4e0d\u662f\u4e00\u4e2a\u5b8c\u6574\u7684\u5bf9\u8c61\uff09\u3002<\/li>\n<li>\u6b64\u65f6t2\u7ebf\u7a0b\u5f00\u59cb\u8fd0\u884c\u4e86\uff0c\u5f53t2\u7ebf\u7a0b\u6267\u884c\u5230<code>if (INSTANCE == null)<\/code>(\u7b2c16\u884c\u4ee3\u7801)\u8bed\u53e5\u7684\u65f6\u5019\uff0ct2\u7ebf\u7a0b\u53d1\u73b0INSTANCE\u4e0d\u4e3a\u7a7a\uff0c\u6b64\u65f6t2\u7ebf\u7a0b\u76f4\u63a5\u8fd4\u56deINSTANCE\u5bf9\u8c61\u3002\u4f46\u662f\u6b64\u65f6\u8be5\u5bf9\u8c61\u8fd8\u662f\u4e00\u4e2a\u4e0d\u5b8c\u6574\u7684\u5bf9\u8c61\uff0c\u5728t2\u7ebf\u7a0b\u4f7f\u7528\u8be5\u5bf9\u8c61\u7684\u65f6\u5019\u5c31\u4f1a\u51fa\u73b0\u95ee\u9898\u3002<\/li>\n<\/ul>\n<p>\u6240\u4ee5\u8bf4\u6307\u4ee4\u91cd\u6392\u5e8f\u5728\u5355\u7ebf\u7a0b\u4e2d\u662f\u4e0d\u4f1a\u6709\u4efb\u4f55\u95ee\u9898\u7684\uff0c\u4f46\u662f\u4e00\u65e6\u6d89\u53ca\u5230\u591a\u7ebf\u7a0b\u7684\u60c5\u51b5\uff0c\u90a3\u4e48\u6307\u4ee4\u91cd\u6392\u5e8f\u53ef\u80fd\u4f1a\u5e26\u6765\u610f\u60f3\u4e0d\u5230\u7684\u7ed3\u679c\u3002<\/p>\n<h2>\u6709\u5e8f\u6027<\/h2>\n<p>\u90a3\u4e48\u65e2\u7136synchronized\u4e0d\u80fd\u7981\u6b62\u6307\u4ee4\u91cd\u6392\u5e8f\uff0c\u90a3\u4e48\u4ed6\u4fdd\u8bc1\u7684\u6709\u5e8f\u6027\u662f\u4ec0\u4e48\u6709\u5e8f\u5462\uff1f<\/p>\n<p>\u5b83\u7684\u672c\u8d28\u662f\u8ba9\u591a\u4e2a\u7ebf\u7a0b\u5728\u8c03\u7528synchronized\u4fee\u9970\u7684\u65b9\u6cd5\u65f6\uff0c\u7531\u5e76\u884c\uff08\u5e76\u53d1\uff09\u53d8\u6210\u4e32\u884c\u8c03\u7528\uff0c\u8c01\u83b7\u5f97\u9501\u8c01\u6267\u884c\u3002<\/p>\n<h3>1\u3001\u4ee3\u7801\u793a\u4f8b<\/h3>\n<p>t1\u3001t2\u4e24\u4e2a\u7ebf\u7a0b\u90fd\u9700\u8981\u53bb\u83b7\u53d6\u5355\u4f8b\u5bf9\u8c61\uff0c\u7136\u540e\u8c03\u7528test\u65b9\u6cd5\uff0c\u5e76\u4e14test\u65b9\u6cd5\u662f\u52a0\u4e86\u540c\u6b65\u9501\u7684\u65b9\u6cd5\u3002<\/p>\n<pre><code>public class MySingleton {\n\n    private static MySingleton INSTANCE;\n\n    private MySingleton() {\n    }\n\n    public static MySingleton getInstance() {\n        if (INSTANCE == null) {\n            synchronized (MySingleton.class) {\n                if (INSTANCE == null) {\n                    INSTANCE = new MySingleton();\n                }\n            }\n        }\n        return INSTANCE;\n    }\n\n    public static void test(final MySingleton singleton) {\n        synchronized (MySingleton.class) {\n            System.out.println(singleton);\n        }\n    }\n}<\/code><\/pre>\n<p>\u6d4b\u8bd5\u4ee3\u7801<\/p>\n<pre><code>public class MySingletonTest {\n  \/\/ \u53ef\u4ee5\u770b\u5230\u4e24\u4e2a\u7ebf\u7a0b\u90fd\u9700\u8981\u53bb\u83b7\u53d6\u5355\u4f8b\u5bf9\u8c61\uff0c\u7136\u540e\u8c03\u7528test\u65b9\u6cd5\uff0c\u5e76\u4e14test\u65b9\u6cd5\u662f\u52a0\u4e86\u540c\u6b65\u9501\u7684\u65b9\u6cd5\n    public static void main(final String[] args) {\n        new Thread(() -&gt; {\n            MySingleton instance = MySingleton.getInstance();\n            MySingleton.test(instance);\n        }, &quot;t1&quot;).start();\n        new Thread(() -&gt; {\n            MySingleton instance = MySingleton.getInstance();\n            MySingleton.test(instance);\n        }, &quot;t2&quot;).start();\n    }\n}<\/code><\/pre>\n<p>\u5373\u4f7f\u662ft2\u7ebf\u7a0b\u83b7\u5f97\u4e86\u672a\u8c03\u7528\u6784\u9020\u51fd\u6570\u7684\u5bf9\u8c61\uff0c\u90a3\u4e48\u5728t2\u7ebf\u7a0b\u4e2d\u518d\u53bb\u8c03\u7528<code>MySingleton.test(instance);<\/code>\u65b9\u6cd5\u7684\u65f6\u5019\uff0c\u4e5f\u5e76\u4e0d\u4f1a\u51fa\u73b0\u4efb\u4f55\u95ee\u9898\uff0c\u56e0\u4e3a\u4f7f\u7528\u4e86\u540c\u6b65\u9501\uff0c\u6bcf\u4e2a\u4e00\u52a0\u9501\u6267\u884c\u7684\u65b9\u6cd5\u90fd\u53d8\u6210\u4e86\u4e32\u884c\uff0c\u5c06\u5e76\u53d1\u6267\u884c\u53d8\u6210\u4e86\u4e32\u884c\uff0c\u5f53t2\u7ebf\u7a0b\u83b7\u53d6\u5230\u9501\u7136\u540e\u6267\u884c\u7684\u65f6\u5019\uff0ct1\u65e9\u5df2\u7ecf\u91ca\u653e\u4e86\u9501\uff0c\u6b64\u65f6instance\u4e5f\u5df2\u7ecf\u65e9\u5c31\u88ab\u5b9e\u4f8b\u5316\u597d\u4e86\u3002\u6240\u4ee5\u4e0d\u4f1a\u51fa\u73b0\u95ee\u9898\u3002<\/p>\n<p><strong>\u6240\u4ee5synchronized\u4fdd\u8bc1\u987a\u5e8f\u6027\u662f\u6307\u7684\u5c06\u5e76\u53d1\u6267\u884c\u53d8\u6210\u4e86\u4e32\u884c\uff0c\u4f46\u5e76\u4e0d\u80fd\u4fdd\u8bc1\u5185\u90e8\u6307\u4ee4\u91cd\u6392\u5e8f\u95ee\u9898\u3002<\/strong><\/p>\n<p>\u6765\u6e90\uff1ablog.csdn.net\/Hellowenpan\/article\/details\/117750543<\/p>\n<p><strong>\u8fd1\u671f\u70ed\u6587\u63a8\u8350\uff1a<\/strong><\/p>\n<p>1.<a target=\"_blank\" href=\"https:\/\/link.segmentfault.com\/?enc=XYVr4NJRAwbHdc0JOaB2TA%3D%3D.wVqp7GycgjrH4a0OQnJC84h0o2lial0kpQNBkOURYOw%3D\" rel=\"noopener noreferrer\">1,000+ \u9053 Java\u9762\u8bd5\u9898\u53ca\u7b54\u6848\u6574\u7406(2022\u6700\u65b0\u7248)<\/a><\/p>\n<p>2.<a target=\"_blank\" href=\"https:\/\/link.segmentfault.com\/?enc=139YSEkBIwRPs5UeoUxxRQ%3D%3D.QOPKakSKgZdeWFmSwq%2FGxOTiSxD6mdv3ZpJ0UygQpG7uMydU0IBZYoa31%2Bt%2FNhorRvppM2IsU1Oy157BDPOLAQ%3D%3D\" rel=\"noopener noreferrer\">\u52b2\u7206\uff01Java \u534f\u7a0b\u8981\u6765\u4e86\u3002\u3002\u3002<\/a><\/p>\n<p>3.<a target=\"_blank\" href=\"https:\/\/link.segmentfault.com\/?enc=TWZHqfmbut5kW7X%2Bd0doag%3D%3D.GzUVpTRzQW1Zjw2%2FKW3vOcRMQ1CeqP2qVancHhgIoqQUfMuDMV6GbnQwIA6L%2FIQ0\" rel=\"noopener noreferrer\">Spring Boot 2.x \u6559\u7a0b\uff0c\u592a\u5168\u4e86\uff01<\/a><\/p>\n<p>4.<a target=\"_blank\" href=\"https:\/\/link.segmentfault.com\/?enc=t%2BVZdpHc6Pa%2BP6jeNK1HsA%3D%3D.7jGT0zTPc65W3kGn9clbetGPStZSc2g1sgMa19T5GS8bvyGpRC59fVoXeLLbDHExghRG6wKqYWAQiKOykqMZWA%3D%3D\" rel=\"noopener noreferrer\">\u522b\u518d\u5199\u6ee1\u5c4f\u7684\u7206\u7206\u7206\u70b8\u7c7b\u4e86\uff0c\u8bd5\u8bd5\u88c5\u9970\u5668\u6a21\u5f0f\uff0c\u8fd9\u624d\u662f\u4f18\u96c5\u7684\u65b9\u5f0f\uff01\uff01<\/a><\/p>\n<p>5.<a target=\"_blank\" href=\"https:\/\/link.segmentfault.com\/?enc=1jL3FN51sXRlsuGEP0ShUg%3D%3D.qSXufp6vhnityvgGkKnTeJht9yjSy58eQZbNZyDGoZz4dZjFL26ZdFO1uWpJyQVJ8prWuN3qa42%2BW58boMgIsk1SrdznIdh7zqLMHn5jXdk%3D\" rel=\"noopener noreferrer\">\u300aJava\u5f00\u53d1\u624b\u518c\uff08\u5d69\u5c71\u7248\uff09\u300b\u6700\u65b0\u53d1\u5e03\uff0c\u901f\u901f\u4e0b\u8f7d\uff01<\/a><\/p>\n<p>\u89c9\u5f97\u4e0d\u9519\uff0c\u522b\u5fd8\u4e86\u968f\u624b\u70b9\u8d5e+\u8f6c\u53d1\u54e6\uff01<\/p>\n<p><a href=\"https:\/\/segmentfault.com\/a\/1190000044161646\">https:\/\/segmentfault.com\/a\/1190000044161646<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u6307\u4ee4\u91cd\u6392\u5e8f 1\u3001\u95ee\u9898\u63cf\u8ff0 \u9996\u5148\u4e00\u5b9a\u8981\u660e\u786e\uff1a\u6307\u4ee4\u91cd\u6392\u5e8f\u548c\u6709\u5e8f\u6027\u662f\u4e0d\u4e00\u6837\u7684\u3002\u8fd9\u4e00\u70b9\u975e\u5e38\u91cd\u8981\u3002 \u6211\u4eec\u7ecf\u5e38\u90fd\u4f1a\u8fd9\u4e48\u8bf4\uff1a [&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-10008192","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\/10008192","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=10008192"}],"version-history":[{"count":0,"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts\/10008192\/revisions"}],"wp:attachment":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=10008192"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=10008192"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=10008192"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}