全局唯一标识符(GUID,Globally Unique Identifier)也称作 UUID(Universally Unique IDentifier) 。
GUID是一种由算法生成的二进制长度为128位的数字标识符。GUID 的格式为“xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx”,其中的 x 是 0-9 或 a-f 范围内的一个32位十六进制数。在理想情况下,任何计算机和计算机集群都不会生成两个相同的GUID。
GUID 的总数达到了2^128(3.4×10^38)个,所以随机生成两个相同GUID的可能性非常小,但并不为0。GUID一词有时也专指微软对UUID标准的实现。
算法1
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function uuid()
{ var s
= []; var hexDigits
= "0123456789abcdef" ; for ( var i
= 0; i < 36; i++) { s[i]
= hexDigits.substr(Math.floor(Math.random() * 0x10), 1); } s[14]
= "4" ; //
bits 12-15 of the time_hi_and_version field to 0010 s[19]
= hexDigits.substr((s[19] & 0x3) | 0x8, 1); //
bits 6-7 of the clock_seq_hi_and_reserved to 01 s[8]
= s[13] = s[18] = s[23] = "-" ; var uuid
= s.join( "" ); return uuid; } |
算法2
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function guid()
{ return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx' .replace(/[xy]/g, function (c)
{ var r
= Math.random()*16|0, v = c == 'x' ?
r : (r&0x3|0x8); return v.toString(16); }); } |
算法3
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function guid()
{ function S4()
{ return (((1+Math.random())*0x10000)|0).toString(16).substring(1); } return (S4()+S4()+ "-" +S4()+ "-" +S4()+ "-" +S4()+ "-" +S4()+S4()+S4()); } |
算法4
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function uuid(len,
radix) { var chars
= '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz' .split( '' ); var uuid
= [], i; radix
= radix || chars.length; if (len)
{ //
Compact form for (i
= 0; i < len; i++) uuid[i] = chars[0 | Math.random()*radix]; } else { //
rfc4122, version 4 form var r; //
rfc4122 requires these characters uuid[8]
= uuid[13] = uuid[18] = uuid[23] = '-' ; uuid[14]
= '4' ; //
Fill in random data. At i==19 set the high bits of clock sequence as //
per rfc4122, sec. 4.1.5 for (i
= 0; i < 36; i++) { if (!uuid[i])
{ r
= 0 | Math.random()*16; uuid[i]
= chars[(i == 19) ? (r & 0x3) | 0x8 : r]; } } } return uuid.join( '' ); } |
这个可以指定长度和基数。比如
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//
8 character ID (base=2) uuid(8,
2) //
"01001010" //
8 character ID (base=10) uuid(8,
10) //
"47473046" //
8 character ID (base=16) uuid(8,
16) //
"098F4D35" |
来源:CSDN
作者:qq_32311977
链接:https://blog.csdn.net/qq_32311977/article/details/49611957