您可以像这样使用 _ RFC5322_
（参考正则表达式已修改）
"(?im)^(?=.{1,64}@)(?:("[^"\\]*(?:\\.[^"\\]*)*"@)|((?:[0-9a-z](?:\.(?!\.)|[-!#\$%&'\*\+/=\?\^`\{\}\|~\w])*)?[0-9a-z]@))(?=.{1,255}$)(?:(\[(?:\d{1,3}\.){3}\d{1,3}\])|((?:(?=.{1,63}\.)[0-9a-z][-\w]*[0-9a-z]*\.)+[a-z0-9][\-a-z0-9]{0,22}[a-z0-9])|((?=.{1,63}$)[0-9a-z][-\w]*))$"https://regex101.com/r/ObS3QZ/1
# (?im)^(?=.{1,64}@)(?:("[^"\]*(?:\.[^"\]*)*"@)|((?:[0-9a-z](?:.(?!.)|[-!#$%&'*+/=?^`{}|~w])*)?[0-9a-z]@))(?=.{1,255}$)(?:([(?:d{1,3}.){3}d{1,3}])|((?:(?=.{1,63}.)[0-9a-z][-w]*[0-9a-z]*.)+[a-z0-9][-a-z0-9]{0,22}[a-z0-9])|((?=.{1,63}$)[0-9a-z][-w]*))$ # Note - remove all comments '(comments)' before runninig this regex # Find ([^)]*) replace with nothing (?im) # Case insensitive ^ # BOS # Local part (?= .{1,64} @ ) # 64 max chars (?: ( # (1 start), Quoted" [^"\]* (?: \ . [^"\]* )*"@ ) # (1 end) | # or, ( # (2 start), Non-quoted(?: [0-9a-z] (?: . (?! . ) | # or,[-!#$%&'*+/=?^`{}|~w] )*)?[0-9a-z] @ ) # (2 end) ) # Domain part (?= .{1,255} $ ) # 255 max chars (?: ( # (3 start), IP[(?: d{1,3} . ){3}d{1,3} ] ) # (3 end) | # or, ( # (4 start), Others(?: # Labels (63 max chars each) (?= .{1,63} . ) [0-9a-z] [-w]* [0-9a-z]* .)+[a-z0-9] [-a-z0-9]{0,22} [a-z0-9] ) # (4 end) | # or, ( # (5 start), Localdomain(?= .{1,63} $ )[0-9a-z] [-w]* ) # (5 end) ) $ # EOSHow make sudhansu_@gmail.com this as valid email ID – Mihir Feb 7 at 9:34
我认为规范希望将局部部分用引号引起来，
或将其用引起来
[0-9a-z]。
但是，要避开以后并使之
sudhansu_@gmail.com生效，只需
将第2组替换为：
( # (2 start), Non-quoted[0-9a-z] (?: . (?! . ) | # or, [-!#$%&'*+/=?^`{}|~w] )*@ ) # (2 end)新正则表达式
"(?im)^(?=.{1,64}@)(?:("[^"\\]*(?:\\.[^"\\]*)*"@)|([0-9a-z](?:\.(?!\.)|[-!#\$%&'\*\+/=\?\^`\{\}\|~\w])*@))(?=.{1,255}$)(?:(\[(?:\d{1,3}\.){3}\d{1,3}\])|((?:(?=.{1,63}\.)[0-9a-z][-\w]*[0-9a-z]*\.)+[a-z0-9][\-a-z0-9]{0,22}[a-z0-9])|((?=.{1,63}$)[0-9a-z][-\w]*))$"新演示
https://regex101.com/r/ObS3QZ/5
