{"id":1613,"date":"2018-08-17T17:36:31","date_gmt":"2018-08-17T09:36:31","guid":{"rendered":"https:\/\/damogame.cn:15443\/wordpress\/?p=1613"},"modified":"2018-08-17T17:36:31","modified_gmt":"2018-08-17T09:36:31","slug":"%e5%88%86%e5%b8%83%e5%bc%8f%e9%ab%98%e5%b9%b6%e5%8f%91%e4%b8%8b%e5%94%af%e4%b8%80%e6%a0%87%e8%af%86snowflake%e7%ae%97%e6%b3%95","status":"publish","type":"post","link":"https:\/\/i007.cc\/wordpress\/archives\/1613","title":{"rendered":"\u5206\u5e03\u5f0f\u9ad8\u5e76\u53d1\u4e0b\u552f\u4e00\u6807\u8bc6snowflake\u7b97\u6cd5"},"content":{"rendered":"
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\u5206\u5e03\u5f0f\u9ad8\u5e76\u53d1\u4e0b\u552f\u4e00\u6807\u8bc6snowflake\u7b97\u6cd5<\/h1>\n<\/div>\n
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2017\u5e7407\u670817\u65e5 17:43:02<\/span><\/p>\n
\u9605\u8bfb\u6570\uff1a2939<\/span><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n
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<\/a>\u7b80\u4ecb\uff1a<\/h3>\n

\u5728\u7cfb\u7edf\u5c0f\u65f6\uff0c\u552f\u4e00\u6807\u8bc6\u7684\u4ea7\u751f\uff0c\u53ef\u4ee5\u5229\u7528\u516c\u7528\u6a21\u5757\u6765\u5904\u7406\uff0c\u6bd4\u5982\u6570\u636e\u5e93\u8868\u7684\u552f\u4e00\u952e\u3001\u6216\u8005\u7f13\u5b58\u7684\u552f\u4e00id\u7b49\u7b49\u65b9\u5f0f\u3002\u4f46\u5728\u5206\u5e03\u5f0f\u9ad8\u5e76\u53d1\u7684\u7cfb\u7edf\u4e2d\uff0c\u5982\u679c\u8fd8\u662f\u8fd9\u6837\u4f7f\u7528\u516c\u5171\u6a21\u5757\uff0c\u5c31\u4f1a\u4ea7\u751f\u5f88\u5927\u7684\u98ce\u9669\u548c\u74f6\u9888\u3002\u7f51\u4e0a\u4e5f\u6709\u76f8\u5173\u63a8\u8350\u7684\uff0ctwitter\u7684snowflake\u5c31\u80fd\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\u3002<\/p>\n

snowflake\u6ee1\u8db3\u4e86\u4ee5\u4e0b\u4e2a\u8981\u6c42\uff1a
\n1. \u53ea\u752864\u4f4d\u5c31\u80fd\u8fbe\u5230\u8981\u6c42\uff1b\u800c\u65e0\u9700128\u7684\u65b9\u5f0f\u3002
\n2. \u8003\u8651\u5230\u6392\u5e8f\u7684\u8981\u6c42\uff0c\u6807\u8bc6\u7684\u6392\u5e8f\u8ddf\u65f6\u95f4\u4e0a\u57fa\u672c\u80fd\u4fdd\u6301\u4e00\u81f4\u3002
\n3. \u6ee1\u8db3\u4e86\u9884\u671f\u670d\u52a1\u65f6\u95f4\u5185\u7684\uff0c\u5373\u5728\u591a\u5c11\u5e74\u5185\u6b64\u7b97\u6cd5\u9002\u7528\u3002<\/p>\n

<\/a>snowflake\u7b97\u6cd5\u6838\u5fc3\uff1a<\/h3>\n

\"\u8fd9\u91cc\u5199\u56fe\u7247\u63cf\u8ff0\"<\/p>\n

\u5982\u56fe\uff0c64\u4f4d\u3002\u4e3b\u8981\u75313\u5757\u6784\u6210\uff1a\u65f6\u95f4\u6233\u3001\u5de5\u4f5c\u673a\u5668id\u3001\u5e8f\u5217\u53f7\u3002
\n– \u5176\u4e2d\u7b2c\u4e00\u4f4d\u4e0d\u7528\uff0c\u4e5f\u53ef\u4ee5\u7406\u89e3\u4f5c\u4e3a\u6b63\u8d1f\u6570\u6765\u4f7f\u7528\uff0c\u9ed8\u8ba4\u6b63\u6570\u7684\u3002
\n– \u968f\u540e41\u4f4d\u8868\u793a\u65f6\u95f4\u6233\uff0c\u5728\u5b9e\u9645\u4f7f\u7528\u65f6\uff0c\u53ef\u4ee5\u5f53\u505a\u65f6\u95f4\u5dee\u6765\u4f7f\u7528\uff0c\u6bd4\u5982\u73b0\u5728\u79bb2017-01-01 00:00:00\u7684\u65f6\u95f4\u5dee\u3002\u8fd9\u6837\u7684\u8bdd\uff0c\u65f6\u95f4\u8303\u56f4\u5c31\u80fd\u8fbe\u5230\uff1a (2^41-1)\/(1000*60*60*24*365)=69.7\u5e74\u3002
\n– \u4e2d\u95f410\u4f4d\u7528\u4e8e\u5de5\u4f5c\u673a\u5668\u7684\u3002\u53ef\u4ee5\u7528\u4e8e 2^10-1=1023\u53f0\u673a\u5668\u3002
\n– \u6700\u540e12\u4f4d\u8868\u793a\u5e8f\u5217\u53f7\uff0c\u4e00\u4e2a\u673a\u5668\u5728\u4e00\u4e2a\u6beb\u79d2\u65f6\u6700\u5927\u80fd\u4ea7\u751f 2^12-1=4095\u4e2a\u3002
\n**\u5728\u5b9e\u9645\u5e94\u7528\u4e2d\uff0c\u53ef\u80fd\u65e0\u9700\u6700\u5927\u5316\u7684\uff0c\u6bd4\u5982\u65f6\u95f4\u6233\u53ea\u752830\u4f4d\u5c31\u80fd\u8fbe\u5230\u8981\u6c42\u7684\u5c31\u65e0\u970041\u4f4d\uff0c\u5176\u4ed6\u7684\u540c\u7406\u3002
\n\u5de5\u4f5c\u673a\u5668ID\uff0c\u53ef\u4ee5\u662f\u8fdb\u7a0b\u7ea7\u522b\u3002\u673a\u5668\u7ea7\u522b\u7684\u8bdd\uff0c\u53ef\u4ee5\u4f7f\u7528\u673a\u5668\u7684mac\u5730\u5740\u6216ip\u5730\u5740\u7ecf\u8fc7\u7b97\u6cd5\uff1b\u5982\u679c\u662f\u8fdb\u7a0b\u7ea7\u522b\u7684\u8bdd\uff0c\u53ef\u4ee5\u4f7f\u7528path+\u8fdb\u7a0b\u6807\u8bc6\uff1b\u4e5f\u53ef\u4ee5\u6df7\u7f16\uff0c\u5217\u5982\u524d5\u4f4d\u6807\u8bc6\u673a\u5668\uff0c\u540e5\u4f4d\u6807\u8bc6\u8fdb\u7a0b\u3002
\n\u5173\u4e8e\u5e8f\u5217\u53f7\u6709\u4e2a\u6ce8\u610f\u70b9\uff0c\u5982\u679c\u4e00\u4e2a\u6beb\u79d2\u5185\uff0c\u5e8f\u5217\u53f7\u5df2\u7ecf\u8fbe\u5230\u4e0a\u9650\uff0c\u5c31\u7b49\u5230\u4e0b\u4e00\u6beb\u79d2\uff0c\u540c\u65f6\u5e8f\u5217\u53f7\u7f6e\u96f6\u5f00\u59cb\u3002**<\/p>\n

<\/a>\u5177\u4f53\u4ee3\u7801\uff1a<\/h3>\n
\r\n\/**\r\n * @author<\/span> zcl\r\n * @date<\/span> 2017\/7\/12\r\n **\/<\/span>\r\npublic<\/span> class<\/span> MagicSnowFlake<\/span> {<\/span>\r\n\r\n    \/\/\u5176\u5b9e\u65f6\u95f4\u6233   2017-01-01 00:00:00<\/span>\r\n    private<\/span> final<\/span> static<\/span> long<\/span> twepoch = 1483200000000<\/span>l;\r\n\r\n    \/\/10bit\uff08\u4f4d\uff09\u7684\u5de5\u4f5c\u673a\u5668id  \u4e2dIP\u6807\u8bc6\u6240\u5360\u7684\u4f4d\u6570 8bit\uff08\u4f4d\uff09<\/span>\r\n    private<\/span> final<\/span> static<\/span> long<\/span> ipIdBits = 8<\/span>L;\r\n\r\n    \/\/IP\u6807\u8bc6\u6700\u5927\u503c 255  \u53732\u76848\u6b21\u65b9\u51cf\u4e00\u3002<\/span>\r\n    private<\/span> final<\/span> static<\/span> long<\/span> ipIdMax = ~ (-1<\/span>L << ipIdBits);\r\n\r\n    \/\/10bit\uff08\u4f4d\uff09\u7684\u5de5\u4f5c\u673a\u5668id  \u4e2d\u6570\u5b57\u6807\u8bc6id\u6240\u5360\u7684\u4f4d\u6570 2bit\uff08\u4f4d\uff09<\/span>\r\n    private<\/span> final<\/span> static<\/span> long<\/span> dataCenterIdBits = 2<\/span>L;\r\n\r\n    \/\/\u6570\u5b57\u6807\u8bc6id\u6700\u5927\u503c 3  \u53732\u76842\u6b21\u65b9\u51cf\u4e00\u3002<\/span>\r\n    private<\/span> final<\/span> static<\/span> long<\/span> dataCenterIdMax = ~ (-1<\/span>L << dataCenterIdBits);\r\n\r\n    \/\/\u5e8f\u5217\u5728id\u4e2d\u5360\u7684\u4f4d\u6570 12bit<\/span>\r\n    private<\/span> final<\/span> static<\/span> long<\/span> seqBits = 12<\/span>L;\r\n\r\n    \/\/\u5e8f\u5217\u6700\u5927\u503c 4095 \u53732\u768412\u6b21\u65b9\u51cf\u4e00\u3002<\/span>\r\n    private<\/span> final<\/span> static<\/span> long<\/span> seqMax = ~(-1<\/span>L << seqBits);\r\n\r\n    \/\/ 64\u4f4d\u7684\u6570\u5b57\uff1a\u9996\u4f4d0  \u968f\u540e41\u4f4d\u8868\u793a\u65f6\u95f4\u6233 \u968f\u540e10\u4f4d\u5de5\u4f5c\u673a\u5668id\uff088\u4f4dIP\u6807\u8bc6 + 2\u4f4d\u6570\u5b57\u6807\u8bc6\uff09 \u6700\u540e12\u4f4d\u5e8f\u5217\u53f7<\/span>\r\n    private<\/span> final<\/span> static<\/span> long<\/span> dataCenterIdLeftShift = seqBits;\r\n    private<\/span> final<\/span> static<\/span> long<\/span> ipIdLeftShift = seqBits + dataCenterIdBits;\r\n    private<\/span> final<\/span> static<\/span> long<\/span> timeLeftShift = seqBits  + dataCenterIdBits + ipIdLeftShift;\r\n\r\n    \/\/IP\u6807\u8bc6(0~255)<\/span>\r\n    private<\/span> long<\/span> ipId;\r\n\r\n    \/\/ \u6570\u636e\u4e2d\u5fc3ID(0~3)<\/span>\r\n    private<\/span> long<\/span> dataCenterId;\r\n\r\n    \/\/ \u6beb\u79d2\u5185\u5e8f\u5217(0~4095)<\/span>\r\n    private<\/span> long<\/span> seq = 0<\/span>L;\r\n\r\n    \/\/ \u4e0a\u6b21\u751f\u6210ID\u7684\u65f6\u95f4\u622a<\/span>\r\n    private<\/span> long<\/span> lastTime = -1<\/span>L;\r\n\r\n    public<\/span> MagicSnowFlake<\/span>(long<\/span> ipId, long<\/span> dataCenterId) {\r\n        if<\/span>(ipId < 0<\/span> || ipId > ipIdMax) {\r\n            System.out.println(\" ---------- ipId\u4e0d\u5728\u6b63\u5e38\u8303\u56f4\u5185(0~\"<\/span>+ipIdMax +\") \"<\/span> + ipId);\r\n            System.exit(0<\/span>);\r\n        }\r\n\r\n        if<\/span>(dataCenterId < 0<\/span> || dataCenterId > dataCenterIdMax) {\r\n            System.out.println(\" ---------- dataCenterId\u4e0d\u5728\u6b63\u5e38\u8303\u56f4\u5185(0~\"<\/span>+dataCenterIdMax +\") \"<\/span> + dataCenterId);\r\n            System.exit(0<\/span>);\r\n        }\r\n\r\n        this<\/span>.ipId = ipId;\r\n        this<\/span>.dataCenterId = dataCenterId;\r\n    }\r\n\r\n    public<\/span> synchronized<\/span> long<\/span> nextId<\/span>() {\r\n        long<\/span> nowTime = System.currentTimeMillis();\r\n\r\n        if<\/span>(nowTime < lastTime) {\r\n            System.out.println(\" ---------- \u5f53\u524d\u65f6\u95f4\u524d\u4e8e\u4e0a\u6b21\u64cd\u4f5c\u65f6\u95f4\uff0c\u5f53\u524d\u65f6\u95f4\u6709\u8bef: \"<\/span> + nowTime);\r\n            System.exit(0<\/span>);\r\n        }\r\n\r\n        if<\/span>(nowTime == lastTime) {\r\n            seq = (seq + 1<\/span>) & seqMax;\r\n            if<\/span>(seq == 0<\/span>) {\r\n                nowTime = getNextTimeStamp();\r\n            }\r\n        } else<\/span> {\r\n            seq = 0<\/span>L;\r\n        }\r\n\r\n        lastTime = nowTime;\r\n\r\n        return<\/span> ((nowTime - twepoch) << timeLeftShift)\r\n                | (ipId << ipIdLeftShift)\r\n                | (dataCenterId << dataCenterIdLeftShift)\r\n                | seq;\r\n    }\r\n\r\n    private<\/span> long<\/span> getNextTimeStamp<\/span>() {\r\n        long<\/span> nowTime;\r\n        do {\r\n            nowTime = System.currentTimeMillis();\r\n        } while<\/span>(nowTime <= lastTime);\r\n        return<\/span> nowTime;\r\n    }\r\n}\r\n\r\n---------------------------------------------------------------\r\n\r\n\/**\r\n * @author<\/span> zcl\r\n * @date<\/span> 2017\/7\/12\r\n **\/<\/span>\r\npublic<\/span> class<\/span> ThreadSnowFlake<\/span> extends<\/span> Thread<\/span> {<\/span>\r\n\r\n    MagicSnowFlake msf;\r\n\r\n    int<\/span> cnt = 0<\/span>;\r\n\r\n    public<\/span> ThreadSnowFlake<\/span>(MagicSnowFlake msf) {\r\n        this<\/span>.msf = msf;\r\n    }\r\n\r\n    public<\/span> void<\/span> run<\/span>() {\r\n        System.out.println();\r\n        if<\/span>(msf != null<\/span>) {\r\n            while<\/span>(cnt < 10<\/span>) {\r\n                System.out.print(Thread.currentThread().getId() + \" : \"<\/span> + msf.nextId());\r\n                cnt ++;\r\n            }\r\n        }\r\n    }\r\n}\r\n\r\n-----------------------------------------------------------------------\r\n\/**\r\n * @author<\/span> zcl\r\n * @date<\/span> 2017\/7\/12\r\n **\/<\/span>\r\npublic<\/span> class<\/span> AlgorithmMain<\/span> {<\/span>\r\n\r\n    public<\/span> static<\/span> void<\/span> main<\/span>(String[] args) {\r\n\r\n        MagicSnowFlake msf = new<\/span> MagicSnowFlake(196<\/span>, 2<\/span>);\r\n\r\n        ThreadSnowFlake t1 = new<\/span> ThreadSnowFlake(msf);\r\n        ThreadSnowFlake t2 = new<\/span> ThreadSnowFlake(msf);\r\n\r\n        t1.start();\r\n        t2.start();\r\n    }\r\n}\r\n<\/code><\/pre>\n