{"id":37251,"date":"2023-12-11T14:40:47","date_gmt":"2023-12-11T06:40:47","guid":{"rendered":"https:\/\/wx.kaifamiao.info\/?p=37251"},"modified":"2023-12-11T14:40:47","modified_gmt":"2023-12-11T06:40:47","slug":"%e8%af%b4%e8%af%b4%e8%87%aa%e5%b7%b1%e6%98%af%e6%80%8e%e4%b9%88%e4%bd%bf%e7%94%a8-synchronized-%e5%85%b3%e9%94%ae%e5%ad%97%ef%bc%8c%e5%9c%a8%e9%a1%b9%e7%9b%ae%e4%b8%ad%e7%94%a8%e5%88%b0%e4%ba%86","status":"publish","type":"post","link":"http:\/\/wx.kaifamiao.info\/index.php\/2023\/12\/11\/%e8%af%b4%e8%af%b4%e8%87%aa%e5%b7%b1%e6%98%af%e6%80%8e%e4%b9%88%e4%bd%bf%e7%94%a8-synchronized-%e5%85%b3%e9%94%ae%e5%ad%97%ef%bc%8c%e5%9c%a8%e9%a1%b9%e7%9b%ae%e4%b8%ad%e7%94%a8%e5%88%b0%e4%ba%86\/","title":{"rendered":"\u8bf4\u8bf4\u81ea\u5df1\u662f\u600e\u4e48\u4f7f\u7528 synchronized \u5173\u952e\u5b57\uff0c\u5728\u9879\u76ee\u4e2d\u7528\u5230\u4e86\u5417\uff1f\u91cd\u8981"},"content":{"rendered":"<p>&#8220;`&#8221;                    <img decoding=\"async\" src=\"\"http:\/\/res.mianshigee.com\/upload\/article\/20200424\/8f1258ba-28ae-49ac-ac02-a309da5764a3.png\"\" alt=\"\"Synchronized \u5173\u952e\u5b57\u4f7f\u7528\u3001\u5e95\u5c42\u539f\u7406\u3001JDK1.6 \u4e4b\u540e\u7684\u5e95\u5c42\u4f18\u5316\u4ee5\u53ca \u548cReenTrantLock \u7684\u5bf9\u6bd4\"\" style=\"\"width: 1211.33px;\"\"><\/p>\n<h3>synchronized\u5173\u952e\u5b57\u6700\u4e3b\u8981\u7684\u4e09\u79cd\u4f7f\u7528\u65b9\u5f0f\u7684\u603b\u7ed3<\/h3>\n<ul>\n<li><strong>\u4fee\u9970\u5b9e\u4f8b\u65b9\u6cd5\uff0c\u4f5c\u7528\u4e8e\u5f53\u524d\u5bf9\u8c61\u5b9e\u4f8b\u52a0\u9501\uff0c\u8fdb\u5165\u540c\u6b65\u4ee3\u7801\u524d\u8981\u83b7\u5f97\u5f53\u524d\u5bf9\u8c61\u5b9e\u4f8b\u7684\u9501<\/strong><\/li>\n<li><strong>\u4fee\u9970\u9759\u6001\u65b9\u6cd5\uff0c\u4f5c\u7528\u4e8e\u5f53\u524d\u7c7b\u5bf9\u8c61\u52a0\u9501\uff0c\u8fdb\u5165\u540c\u6b65\u4ee3\u7801\u524d\u8981\u83b7\u5f97\u5f53\u524d\u7c7b\u5bf9\u8c61\u7684\u9501<\/strong> \u3002\u4e5f\u5c31\u662f\u7ed9\u5f53\u524d\u7c7b\u52a0\u9501\uff0c\u4f1a\u4f5c\u7528\u4e8e\u7c7b\u7684\u6240\u6709\u5bf9\u8c61\u5b9e\u4f8b\uff0c\u56e0\u4e3a\u9759\u6001\u6210\u5458\u4e0d\u5c5e\u4e8e\u4efb\u4f55\u4e00\u4e2a\u5b9e\u4f8b\u5bf9\u8c61\uff0c\u662f\u7c7b\u6210\u5458\uff08 static \u8868\u660e\u8fd9\u662f\u8be5\u7c7b\u7684\u4e00\u4e2a\u9759\u6001\u8d44\u6e90\uff0c\u4e0d\u7ba1new\u4e86\u591a\u5c11\u4e2a\u5bf9\u8c61\uff0c\u53ea\u6709\u4e00\u4efd\uff0c\u6240\u4ee5\u5bf9\u8be5\u7c7b\u7684\u6240\u6709\u5bf9\u8c61\u90fd\u52a0\u4e86\u9501\uff09\u3002\u6240\u4ee5\u5982\u679c\u4e00\u4e2a\u7ebf\u7a0bA\u8c03\u7528\u4e00\u4e2a\u5b9e\u4f8b\u5bf9\u8c61\u7684\u975e\u9759\u6001 synchronized \u65b9\u6cd5\uff0c\u800c\u7ebf\u7a0bB\u9700\u8981\u8c03\u7528\u8fd9\u4e2a\u5b9e\u4f8b\u5bf9\u8c61\u6240\u5c5e\u7c7b\u7684\u9759\u6001 synchronized \u65b9\u6cd5\uff0c\u662f\u5141\u8bb8\u7684\uff0c\u4e0d\u4f1a\u53d1\u751f\u4e92\u65a5\u73b0\u8c61\uff0c<strong>\u56e0\u4e3a\u8bbf\u95ee\u9759\u6001 synchronized \u65b9\u6cd5\u5360\u7528\u7684\u9501\u662f\u5f53\u524d\u7c7b\u7684\u9501\uff0c\u800c\u8bbf\u95ee\u975e\u9759\u6001 synchronized \u65b9\u6cd5\u5360\u7528\u7684\u9501\u662f\u5f53\u524d\u5b9e\u4f8b\u5bf9\u8c61\u9501<\/strong>\u3002<\/li>\n<li><strong>\u4fee\u9970\u4ee3\u7801\u5757\uff0c\u6307\u5b9a\u52a0\u9501\u5bf9\u8c61\uff0c\u5bf9\u7ed9\u5b9a\u5bf9\u8c61\u52a0\u9501\uff0c\u8fdb\u5165\u540c\u6b65\u4ee3\u7801\u5e93\u524d\u8981\u83b7\u5f97\u7ed9\u5b9a\u5bf9\u8c61\u7684\u9501\u3002<\/strong> \u548c synchronized \u65b9\u6cd5\u4e00\u6837\uff0csynchronized(this)\u4ee3\u7801\u5757\u4e5f\u662f\u9501\u5b9a\u5f53\u524d\u5bf9\u8c61\u7684\u3002synchronized \u5173\u952e\u5b57\u52a0\u5230 static \u9759\u6001\u65b9\u6cd5\u548c synchronized(class)\u4ee3\u7801\u5757\u4e0a\u90fd\u662f\u662f\u7ed9 Class \u7c7b\u4e0a\u9501\u3002\u8fd9\u91cc\u518d\u63d0\u4e00\u4e0b\uff1asynchronized\u5173\u952e\u5b57\u52a0\u5230\u975e static \u9759\u6001\u65b9\u6cd5\u4e0a\u662f\u7ed9\u5bf9\u8c61\u5b9e\u4f8b\u4e0a\u9501\u3002\u53e6\u5916\u9700\u8981\u6ce8\u610f\u7684\u662f\uff1a\u5c3d\u91cf\u4e0d\u8981\u4f7f\u7528 synchronized(String a) \u56e0\u4e3aJVM\u4e2d\uff0c\u5b57\u7b26\u4e32\u5e38\u91cf\u6c60\u5177\u6709\u7f13\u51b2\u529f\u80fd\uff01<\/li>\n<\/ul>\n<p>\u4e0b\u9762\u6211\u5df2\u4e00\u4e2a\u5e38\u89c1\u7684\u9762\u8bd5\u9898\u4e3a\u4f8b\u8bb2\u89e3\u4e00\u4e0b synchronized \u5173\u952e\u5b57\u7684\u5177\u4f53\u4f7f\u7528\u3002<\/p>\n<p>\u9762\u8bd5\u4e2d\u9762\u8bd5\u5b98\u7ecf\u5e38\u4f1a\u8bf4\uff1a\u201c\u5355\u4f8b\u6a21\u5f0f\u4e86\u89e3\u5417\uff1f\u6765\u7ed9\u6211\u624b\u5199\u4e00\u4e0b\uff01\u7ed9\u6211\u89e3\u91ca\u4e00\u4e0b\u53cc\u91cd\u68c0\u9a8c\u9501\u65b9\u5f0f\u5b9e\u73b0\u5355\u4f8b\u6a21\u5f0f\u7684\u539f\u7406\u5457\uff01\u201d<\/p>\n<p><strong>\u53cc\u91cd\u6821\u9a8c\u9501\u5b9e\u73b0\u5bf9\u8c61\u5355\u4f8b\uff08\u7ebf\u7a0b\u5b89\u5168\uff09<\/strong><\/p>\n<p><code><\/code>`javapublic class Singleton {<\/p>\n<pre><code>private volatile static Singleton uniqueInstance;private Singleton() {}public static Singleton getUniqueInstance() {   \/\/\u5148\u5224\u65ad\u5bf9\u8c61\u662f\u5426\u5df2\u7ecf\u5b9e\u4f8b\u8fc7\uff0c\u6ca1\u6709\u5b9e\u4f8b\u5316\u8fc7\u624d\u8fdb\u5165\u52a0\u9501\u4ee3\u7801    if (uniqueInstance == null) {        \/\/\u7c7b\u5bf9\u8c61\u52a0\u9501        synchronized (Singleton.class) {            if (uniqueInstance == null) {                uniqueInstance = new Singleton();            }        }    }    return uniqueInstance;}<\/code><\/pre>\n<p>}<code><\/code>`<\/p>\n<p>\u53e6\u5916\uff0c\u9700\u8981\u6ce8\u610f uniqueInstance \u91c7\u7528 volatile \u5173\u952e\u5b57\u4fee\u9970\u4e5f\u662f\u5f88\u6709\u5fc5\u8981\u3002<\/p>\n<p>uniqueInstance \u91c7\u7528 volatile \u5173\u952e\u5b57\u4fee\u9970\u4e5f\u662f\u5f88\u6709\u5fc5\u8981\u7684\uff0c uniqueInstance = new Singleton(); \u8fd9\u6bb5\u4ee3\u7801\u5176\u5b9e\u662f\u5206\u4e3a\u4e09\u6b65\u6267\u884c\uff1a<\/p>\n<ol>\n<li>\u4e3a uniqueInstance \u5206\u914d\u5185\u5b58\u7a7a\u95f4<\/li>\n<li>\u521d\u59cb\u5316 uniqueInstance<\/li>\n<li>\u5c06 uniqueInstance \u6307\u5411\u5206\u914d\u7684\u5185\u5b58\u5730\u5740<\/li>\n<\/ol>\n<p>\u4f46\u662f\u7531\u4e8e JVM \u5177\u6709\u6307\u4ee4\u91cd\u6392\u7684\u7279\u6027\uff0c\u6267\u884c\u987a\u5e8f\u6709\u53ef\u80fd\u53d8\u6210 1-&gt;3-&gt;2\u3002\u6307\u4ee4\u91cd\u6392\u5728\u5355\u7ebf\u7a0b\u73af\u5883\u4e0b\u4e0d\u4f1a\u51fa\u73b0\u95ee\u9898\uff0c\u4f46\u662f\u5728\u591a\u7ebf\u7a0b\u73af\u5883\u4e0b\u4f1a\u5bfc\u81f4\u4e00\u4e2a\u7ebf\u7a0b\u83b7\u5f97\u8fd8\u6ca1\u6709\u521d\u59cb\u5316\u7684\u5b9e\u4f8b\u3002\u4f8b\u5982\uff0c\u7ebf\u7a0b T1 \u6267\u884c\u4e86 1 \u548c 3\uff0c\u6b64\u65f6 T2 \u8c03\u7528 getUniqueInstance() \u540e\u53d1\u73b0 uniqueInstance \u4e0d\u4e3a\u7a7a\uff0c\u56e0\u6b64\u8fd4\u56de uniqueInstance\uff0c\u4f46\u6b64\u65f6 uniqueInstance \u8fd8\u672a\u88ab\u521d\u59cb\u5316\u3002<\/p>\n<p>\u4f7f\u7528 volatile \u53ef\u4ee5\u7981\u6b62 JVM \u7684\u6307\u4ee4\u91cd\u6392\uff0c\u4fdd\u8bc1\u5728\u591a\u7ebf\u7a0b\u73af\u5883\u4e0b\u4e5f\u80fd\u6b63\u5e38\u8fd0\u884c\u3002<\/p>\n<pre><code>            \"```\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>&#8220;`&#8221; synchronized\u5173\u952e\u5b57\u6700\u4e3b\u8981\u7684\u4e09\u79cd\u4f7f\u7528\u65b9\u5f0f\u7684\u603b\u7ed3 \u4fee\u9970\u5b9e\u4f8b\u65b9\u6cd5\uff0c\u4f5c\u7528\u4e8e [&hellip;]<\/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-37251","post","type-post","status-publish","format-standard","hentry","category-c"],"_links":{"self":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/37251","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=37251"}],"version-history":[{"count":1,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/37251\/revisions"}],"predecessor-version":[{"id":37252,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/37251\/revisions\/37252"}],"wp:attachment":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/media?parent=37251"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/categories?post=37251"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/tags?post=37251"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}