{"id":10006269,"date":"2022-08-21T18:20:06","date_gmt":"2022-08-21T10:20:06","guid":{"rendered":"https:\/\/ityet.com\/?p=10006269"},"modified":"2022-08-21T18:20:06","modified_gmt":"2022-08-21T10:20:06","slug":"%e3%80%90java%e9%9d%a2%e8%af%95%e3%80%91%e5%b9%b6%e5%8f%91%e7%bc%96%e7%a8%8b%e9%ab%98%e9%a2%91%e9%9d%a2%e8%af%95%e9%a2%98%ef%bc%8c%e8%af%b7%e4%bd%a0%e8%af%b4%e4%b8%80%e4%b8%8b%e4%bd%a0%e5%af%b9happens","status":"publish","type":"post","link":"https:\/\/itmax.cn\/?p=10006269","title":{"rendered":"\u3010Java\u9762\u8bd5\u3011\u5e76\u53d1\u7f16\u7a0b\u9ad8\u9891\u9762\u8bd5\u9898\uff0c\u8bf7\u4f60\u8bf4\u4e00\u4e0b\u4f60\u5bf9Happens-Before\u7684\u7406\u89e3"},"content":{"rendered":"<blockquote>\n<p>\u201c\u8bf7\u4f60\u8bf4\u4e00\u4e0b\u4f60\u5bf9Happens-Before\u7684\u7406\u89e3\u201d<\/p>\n<p>\u4f60\u542c\u5230\u8fd9\u4e2a\u95ee\u9898\u7684\u65f6\u5019\uff0c\u77e5\u9053\u600e\u4e48\u56de\u7b54\u5417\uff1f<\/p>\n<p>\u5927\u5bb6\u597d\uff0c\u6211\u662fMic\uff0c\u4e00\u4e2a\u5de5\u4f5c\u4e8614\u5e74\u7684Java\u7a0b\u5e8f\u5458\u3002<\/p>\n<p>\u5e76\u53d1\u7f16\u7a0b\u662f\u9762\u8bd5\u8fc7\u7a0b\u4e2d\u91cd\u70b9\u8003\u5bdf\u7684\u65b9\u5411\uff0c\u80fd\u591f\u8003\u5bdf\u7684\u65b9\u5411\u6709\u5f88\u591a<\/p>\n<p>\u5173\u4e8e\u8fd9\u4e2a\u95ee\u9898\uff0c\u6211\u628a\u9ad8\u624b\u56de\u7b54\u6574\u7406\u5230\u4e8615W\u5b57\u7684\u9762\u8bd5\u6587\u6863\u91cc\u9762\u5927\u5bb6\u53ef\u4ee5\u79c1\u4fe1\u6211\u9886\u53d6<\/p>\n<p>\u4e0b\u9762\u770b\u770b\u9ad8\u624b\u7684\u56de\u7b54\u3002<\/p>\n<\/blockquote>\n<h2>\u9ad8\u624b\uff1a<\/h2>\n<p>\u9996\u5148\uff0cHappens-Before\u662f\u4e00\u79cd\u53ef\u89c1\u6027\u6a21\u578b\uff0c\u4e5f\u5c31\u662f\u8bf4\uff0c\u5728\u591a\u7ebf\u7a0b\u73af\u5883\u4e0b\u3002<\/p>\n<p>\u539f\u672c\u56e0\u4e3a\u6307\u4ee4\u91cd\u6392\u5e8f\u7684\u5b58\u5728\u4f1a\u5bfc\u81f4\u6570\u636e\u7684\u53ef\u89c1\u6027\u95ee\u9898\uff0c\u4e5f\u5c31\u662fA\u7ebf\u7a0b\u4fee\u6539\u67d0\u4e2a\u5171\u4eab\u53d8\u91cf<\/p>\n<p>\u5bf9B\u7ebf\u7a0b\u4e0d\u53ef\u89c1\u3002<\/p>\n<p>\u56e0\u6b64\uff0cJMM\u901a\u8fc7Happens-Before\u5173\u7cfb\u5411\u5f00\u53d1\u4eba\u5458\u63d0\u4f9b\u8de8\u8d8a\u7ebf\u7a0b\u7684\u5185\u5b58\u53ef\u89c1\u6027\u4fdd\u8bc1\u3002<\/p>\n<p>\u5982\u679c\u4e00\u4e2a\u64cd\u4f5c\u7684\u6267\u884c\u7ed3\u679c\u5bf9\u53e6\u5916\u4e00\u4e2a\u64cd\u4f5c\u53ef\u89c1\uff0c\u90a3\u4e48\u8fd9\u4e24\u4e2a\u64cd\u4f5c\u4e4b\u95f4\u5fc5\u7136\u5b58\u5728Happens-Before\u7ba1\u7406\u3002<\/p>\n<p>\u5176\u6b21\uff0cHappens-Before\u5173\u7cfb\u53ea\u662f\u63cf\u8ff0\u7ed3\u679c\u7684\u53ef\u89c1\u6027\uff0c\u5e76\u4e0d\u8868\u793a\u6307\u4ee4\u6267\u884c\u7684\u5148\u540e\u987a\u5e8f\uff0c\u4e5f\u5c31\u662f\u8bf4\u53ea\u8981\u4e0d\u5bf9\u7ed3\u679c\u4ea7\u751f\u5f71\u54cd\uff0c\u4ecd\u7136\u5141\u8bb8\u6307\u4ee4\u7684\u91cd\u6392\u5e8f\u3002<\/p>\n<p>\u6700\u540e\uff0c\u5728JMM\u4e2d\u5b58\u5728\u5f88\u591a\u7684Happens-Before\u89c4\u5219\u3002<\/p>\n<ul>\n<li>\u7a0b\u5e8f\u987a\u5e8f\u89c4\u5219\uff0c\u4e00\u4e2a\u7ebf\u7a0b\u4e2d\u7684\u6bcf\u4e2a\u64cd\u4f5c\uff0chappens-before\u8fd9\u4e2a\u7ebf\u7a0b\u4e2d\u7684\u4efb\u610f\u540e\u7eed\u64cd\u4f5c\uff0c\u53ef\u4ee5\u7b80\u5355\u8ba4\u4e3a\u662fas-if-serial\u4e5f\u5c31\u662f\u4e0d\u7ba1\u600e\u4e48\u91cd\u6392\u5e8f\uff0c\u5355\u7ebf\u7a0b\u7684\u7a0b\u5e8f\u7684\u6267\u884c\u7ed3\u679c\u4e0d\u80fd\u6539\u53d8<\/li>\n<li>\n<p>\u4f20\u9012\u6027\u89c4\u5219\uff0c\u4e5f\u5c31\u662fA Happens-Before B\uff0cB Happens-Before C\u3002<\/p>\n<p>\u5c31\u53ef\u4ee5\u63a8\u5bfc\u51faA Happens-Before C\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000042352952\" alt=\"carbon-202207161517001\" title=\"carbon-202207161517001\" loading=\"lazy\"><\/p>\n<\/li>\n<li>volatile\u53d8\u91cf\u89c4\u5219\uff0c\u5bf9\u4e00\u4e2avolatile\u4fee\u9970\u7684\u53d8\u91cf\u7684\u5199\u4e00\u5b9ahappens-before\u4e8e\u4efb\u610f\u540e\u7eed\u5bf9\u8fd9\u4e2avolatile\u53d8\u91cf\u7684\u8bfb\u64cd\u4f5c<\/li>\n<li>\n<p>\u76d1\u89c6\u5668\u9501\u89c4\u5219\uff0c\u4e00\u4e2a\u7ebf\u7a0b\u5bf9\u4e8e\u4e00\u4e2a\u9501\u7684\u91ca\u653e\u9501\u64cd\u4f5c\uff0c\u4e00\u5b9ahappens-before\u4e0e\u540e\u7eed\u7ebf\u7a0b\u5bf9\u8fd9\u4e2a\u9501\u7684\u52a0\u9501\u64cd\u4f5c\u5728\u8fd9\u4e2a\u573a\u666f\u4e2d\uff0c\u5982\u679c\u7ebf\u7a0bA\u83b7\u5f97\u4e86\u9501\u5e76\u4e14\u628ax\u4fee\u6539\u6210\u4e8612\uff0c\u90a3\u4e48\u540e\u7eed\u7684\u7ebf\u7a0b\u83b7\u5f97\u9501\u4e4b\u540e\u5f97\u5230\u7684x\u7684\u503c\u4e00\u5b9a\u662f12\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000042352953\" alt=\"carbon-202207161517002\" title=\"carbon-202207161517002\" loading=\"lazy\"><\/p>\n<\/li>\n<li>\n<p>\u7ebf\u7a0b\u542f\u52a8\u89c4\u5219\uff0c\u5982\u679c\u7ebf\u7a0bA\u6267\u884c\u64cd\u4f5cThreadB.start(),\u90a3\u4e48\u7ebf\u7a0bA\u7684ThreadB.start()\u4e4b\u524d\u7684\u64cd\u4f5chappens-before\u7ebf\u7a0bB\u4e2d\u7684\u4efb\u610f\u64cd\u4f5c\u3002<\/p>\n<p>\u5728\u8fd9\u6837\u4e00\u4e2a\u573a\u666f\u4e2d\uff0ct1\u7ebf\u7a0b\u542f\u52a8\u4e4b\u524d\u5bf9\u4e8ex=10\u7684\u8d4b\u503c\u64cd\u4f5c\uff0ct1\u7ebf\u7a0b\u542f\u52a8\u4ee5\u540e\u8bfb\u53d6x\u7684\u503c\u4e00\u5b9a\u662f10\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000042352954\" alt=\"carbon-202207161517004\" title=\"carbon-202207161517004\" loading=\"lazy\"><\/p>\n<\/li>\n<li>\n<p>join\u89c4\u5219\uff0c\u5982\u679c\u7ebf\u7a0bA\u6267\u884c\u64cd\u4f5cThreadB.join()\u5e76\u6210\u529f\u8fd4\u56de\uff0c\u90a3\u4e48\u7ebf\u7a0bB\u4e2d\u7684\u4efb\u610f\u64cd\u4f5chappens-before\u4e8e\u7ebf\u7a0bA\u4eceThreadB.join()\u64cd\u4f5c\u6210\u529f\u7684\u8fd4\u56de\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000042352955\" alt=\"carbon-202207161517005\" title=\"carbon-202207161517005\" loading=\"lazy\"><\/p>\n<\/li>\n<\/ul>\n<h2>\u603b\u7ed3<\/h2>\n<p>Happens-Before\u6a21\u578b\uff0c\u5728\u591a\u7ebf\u7a0b\u5f00\u53d1\u4e2d\u662f\u5fc5\u987b\u8981\u7406\u89e3\u548c\u638c\u63e1\u7684\u89c4\u5219\u3002<\/p>\n<p>\u5b83\u80fd\u591f\u6307\u5f15\u5f00\u53d1\u8005\u5728\u4f7f\u7528\u591a\u7ebf\u7a0b\u5f00\u53d1\u7684\u65f6\u5019\u907f\u514d\u51fa\u73b0\u5185\u5b58\u53ef\u89c1\u6027\u95ee\u9898<\/p>\n<p>\u56e0\u6b64\u8fd9\u9053\u9762\u8bd5\u9898\u5176\u5b9e\u4e5f\u662f\u8003\u5bdf\u6c42\u804c\u8005\u7684\u57fa\u7840\u80fd\u529b<\/p>\n<p>\u5927\u5bb6\u8bb0\u5f97\u70b9\u8d5e\u6536\u85cf\u52a0\u5173\u6ce8\uff01\uff01\uff01<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000042352956\" alt=\"file\" title=\"file\" loading=\"lazy\"><\/p>\n<blockquote><p>\u7248\u6743\u58f0\u660e\uff1a\u672c\u535a\u5ba2\u6240\u6709\u6587\u7ae0\u9664\u7279\u522b\u58f0\u660e\u5916\uff0c\u5747\u91c7\u7528 CC BY-NC-SA 4.0 \u8bb8\u53ef\u534f\u8bae\u3002\u8f6c\u8f7d\u8bf7\u6ce8\u660e\u6765\u81ea <code>Mic\u5e26\u4f60\u5b66\u67b6\u6784<\/code>\uff01<br \/>\u5982\u679c\u672c\u7bc7\u6587\u7ae0\u5bf9\u60a8\u6709\u5e2e\u52a9\uff0c\u8fd8\u8bf7\u5e2e\u5fd9\u70b9\u4e2a\u5173\u6ce8\u548c\u8d5e\uff0c\u60a8\u7684\u575a\u6301\u662f\u6211\u4e0d\u65ad\u521b\u4f5c\u7684\u52a8\u529b\u3002\u6b22\u8fce\u5173\u6ce8\u540c\u540d\u5fae\u4fe1\u516c\u4f17\u53f7\u83b7\u53d6\u66f4\u591a\u6280\u672f\u5e72\u8d27\uff01<\/p><\/blockquote>\n<p><a href=\"https:\/\/segmentfault.com\/a\/1190000042352950\">https:\/\/segmentfault.com\/a\/1190000042352950<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u201c\u8bf7\u4f60\u8bf4\u4e00\u4e0b\u4f60\u5bf9Happens-Before\u7684\u7406\u89e3\u201d \u4f60\u542c\u5230\u8fd9\u4e2a\u95ee\u9898\u7684\u65f6\u5019\uff0c\u77e5\u9053\u600e\u4e48\u56de\u7b54\u5417\uff1f \u5927\u5bb6\u597d\uff0c\u6211\u662fMi [&hellip;]<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[],"tags":[],"class_list":["post-10006269","post","type-post","status-publish","format-standard","hentry"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts\/10006269","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"}],"replies":[{"embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=10006269"}],"version-history":[{"count":0,"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts\/10006269\/revisions"}],"wp:attachment":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=10006269"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=10006269"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=10006269"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}