{"id":37,"date":"2023-02-21T08:34:07","date_gmt":"2023-02-21T08:34:07","guid":{"rendered":"https:\/\/blessingcr.com\/?p=37"},"modified":"2023-02-21T08:34:11","modified_gmt":"2023-02-21T08:34:11","slug":"volatile","status":"publish","type":"post","link":"https:\/\/blessingcr.com\/?p=37","title":{"rendered":"volatile"},"content":{"rendered":"\n

\u5728 Java \u4e2d\uff0cvolatile \u5173\u952e\u5b57\u53ef\u4ee5\u4fdd\u8bc1\u53d8\u91cf\u7684\u53ef\u89c1\u6027\uff0c\u5982\u679c\u6211\u4eec\u5c06\u53d8\u91cf\u58f0\u660e\u4e3a volatile \uff0c\u8fd9\u5c31\u6307\u793a JVM\uff0c\u8fd9\u4e2a\u53d8\u91cf\u662f\u5171\u4eab\u4e14\u4e0d\u7a33\u5b9a\u7684\uff0c\u6bcf\u6b21\u4f7f\u7528\u5b83\u90fd\u5230\u4e3b\u5b58\u4e2d\u8fdb\u884c\u8bfb\u53d6\u3002<\/p>\n\n\n\n

<\/div>
<\/div><\/div><\/div>\"error\"<\/figure><\/figure>\n\n\n\n

volatile \u5173\u952e\u5b57\u80fd\u4fdd\u8bc1\u6570\u636e\u7684\u53ef\u89c1\u6027\uff0c\u4f46\u4e0d\u80fd\u4fdd\u8bc1\u6570\u636e\u7684\u539f\u5b50\u6027\u3002synchronized \u5173\u952e\u5b57\u4e24\u8005\u90fd\u80fd\u4fdd\u8bc1\u3002<\/p>\n\n\n\n

\u53cc\u91cd\u6821\u9a8c\u9501\u5b9e\u73b0\u5bf9\u8c61\u5355\u4f8b\uff08\u7ebf\u7a0b\u5b89\u5168\uff09<\/strong><\/p>\n\n\n\n

public class Singleton {<\/p>\n\n\n\n

   private volatile static Singleton uniqueInstance;<\/p>\n\n\n\n

   private Singleton() {<\/p>\n\n\n\n

   }<\/p>\n\n\n\n

   public  static Singleton getUniqueInstance() {<\/p>\n\n\n\n

       \/\/\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<\/p>\n\n\n\n

       if (uniqueInstance == null) {<\/p>\n\n\n\n

           \/\/\u7c7b\u5bf9\u8c61\u52a0\u9501<\/p>\n\n\n\n

           synchronized (Singleton.class) {<\/p>\n\n\n\n

               if (uniqueInstance == null) {<\/p>\n\n\n\n

                    uniqueInstance = new Singleton();<\/p>\n\n\n\n

               }<\/p>\n\n\n\n

           }<\/p>\n\n\n\n

       }<\/p>\n\n\n\n

       return uniqueInstance;<\/p>\n\n\n\n

   }<\/p>\n\n\n\n

}<\/p>\n\n\n\n

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\n\n\n

    \n
  1. \u4e3a uniqueInstance \u5206\u914d\u5185\u5b58\u7a7a\u95f4<\/li>\n<\/ol>\n\n\n\n
      \n
    1. \u521d\u59cb\u5316 uniqueInstance<\/li>\n<\/ol>\n\n\n\n
        \n
      1. \u5c06 uniqueInstance \u6307\u5411\u5206\u914d\u7684\u5185\u5b58\u5730\u5740<\/li>\n<\/ol>\n\n\n\n

        \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->3->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","protected":false},"excerpt":{"rendered":"

        \u5728 Java \u4e2d\uff0cvolatile \u5173\u952e\u5b57\u53ef\u4ee5\u4fdd\u8bc1\u53d8\u91cf\u7684\u53ef\u89c1\u6027\uff0c\u5982\u679c\u6211\u4eec\u5c06\u53d8\u91cf\u58f0\u660e\u4e3a volatile \uff0c\u8fd9\u5c31 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[],"class_list":["post-37","post","type-post","status-publish","format-standard","hentry","category-6"],"_links":{"self":[{"href":"https:\/\/blessingcr.com\/index.php?rest_route=\/wp\/v2\/posts\/37","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blessingcr.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blessingcr.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blessingcr.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blessingcr.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=37"}],"version-history":[{"count":1,"href":"https:\/\/blessingcr.com\/index.php?rest_route=\/wp\/v2\/posts\/37\/revisions"}],"predecessor-version":[{"id":38,"href":"https:\/\/blessingcr.com\/index.php?rest_route=\/wp\/v2\/posts\/37\/revisions\/38"}],"wp:attachment":[{"href":"https:\/\/blessingcr.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=37"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blessingcr.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=37"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blessingcr.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=37"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}