I need to perform the following check:
IF myString.contains()
ANY CHARACTERS OTHER THAN
letters a-z, A-Z, "_", "-", numbers 0-9
THEN .....
whats is the correct java syntax for such a check?
2
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You could use a regex to split the string on those characters and check whether the resulting groups are non-empty.G. Bach– G. Bach2013-02-04 12:03:15 +00:00Commented Feb 4, 2013 at 12:03
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1The typical Java programmer will probably use a suitable regex pattern match, no?TheBlastOne– TheBlastOne2013-02-04 12:03:36 +00:00Commented Feb 4, 2013 at 12:03
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3 Answers
You could use a regular expression
Pattern badChar = Pattern.compile("[^A-Za-z0-9_-]");
if(badChar.matcher(myString).find()) {
// ...
}
This pattern will match any single character apart from letters, numbers, underscore and hyphen.
8 Comments
G. Bach
I'm not very good with regexes, so I'm curious: does the last "-" really need no escaping? Seems a bit odd to me if so since that would mean it's interpreted as a literal there whereas in "A-Z" it's interpreted as syntax.
Ian Roberts
@G.Bach yes, a hyphen between two other characters denotes a range, but at the beginning or end of a character class expression it is a literal hyphen.
Droidman
this works, thanks. BTW, would it work with cyrillic characters?
G. Bach
@IanRoberts This means that usually hyphens require escaping, the exception being if they are at the beginning or end of a group of the regex?
Ian Roberts
@Maver1ck a cyrillic letter is not A-Z, a-z, 0-9, underscore or hyphen so if
myString contains one then find would return true. If you want to allow non-Latin letters you could use "[^\p{L}0-9_-]" - \p{L} matches any character that is a "letter" according to the Unicode standard. |
myString.matches("[^a-zA-Z0-9_-]*");
2 Comments
Ian Roberts
You probably want to add a
* or + to that to allow for a string with more than one character.
Kevin Bowersox
@IanRoberts I just realized that, I was also forgetting to negate the content. Thanks
This Will Do it
String str1 = "abc,pqr"; Pattern pattern = Pattern.compile("^[a-zA-Z0-9._,-]+");
Matcher matcher1 = pattern.matcher(str1);
System.out.println(matcher1.matches());
