问题描述
我正在为密码验证创建一个regexp，以便在Java应用程序中用作配置参数。
I'm creating a regexp for password validation to be used in a Java application as a configuration parameter.
正则表达式是：
^.*(?=.{8,})(?=..*[0-9])(?=.*[a-z])(?=.*[A-Z])(?=.*[@#$%^&+=]).*$
密码政策是：
-
至少8个字符
At least 8 chars
包含至少一位数
包含至少一个低位字母和一位高位字母
Contains at least one lower alpha char and one upper alpha char
在一组特殊字符中包含至少一个字符（ @＃％$ ^ 等）
Contains at least one char within a set of special chars (@#%$^ etc.)
不包含空格，标签等。
我只缺少第5点。我无法检查空格，制表符，回车等等的正则表达式。
I’m missing just point 5. I'm not able to have the regexp check for space, tab, carriage return, etc.
有人可以帮助我吗？
推荐答案
试试这个：
^(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z])(?=.*[@#$%^&+=])(?=\S+$).{8,}$
说明：
^ # start-of-string
(?=.*[0-9]) # a digit must occur at least once
(?=.*[a-z]) # a lower case letter must occur at least once
(?=.*[A-Z]) # an upper case letter must occur at least once
(?=.*[@#$%^&+=]) # a special character must occur at least once
(?=\S+$) # no whitespace allowed in the entire string
.{8,} # anything, at least eight places though
$ # end-of-string
添加，修改或删除单个规则很容易，因为每个规则都是独立的模块。
It's easy to add, modify or remove individual rules, since every rule is an independent "module".
（？=。* [xyz]）构造吃掉整个字符串（。* ）并回溯到 [xyz] 匹配的第一个匹配项。如果找到 [xyz] ，则成功，否则失败。
The (?=.*[xyz]) construct eats the entire string (.*) and backtracks to the first occurrence where [xyz] can match. It succeeds if [xyz] is found, it fails otherwise.
替代方案是使用不情愿的限定符：（？=。*？[xyz]）。对于密码检查，这几乎没有任何区别，对于更长的字符串，它可能是更有效的变体。
The alternative would be using a reluctant qualifier: (?=.*?[xyz]). For a password check, this will hardly make any difference, for much longer strings it could be the more efficient variant.
最有效的变体（但最难阅读和维护当然，最容易出错的是（？= [^ xyz] * [xyz]）。对于这个长度的正则表达式并且为了这个目的，我不建议这样做，因为它没有实际的好处。
The most efficient variant (but hardest to read and maintain, therefore the most error-prone) would be (?=[^xyz]*[xyz]), of course. For a regex of this length and for this purpose, I would dis-recommend doing it that way, as it has no real benefits.
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