Initially, I had a requirement that I should check whether a given string follows following two patterns.
"^(.{1,5})?$" --It is meant to check whether the string is of length up to 5 characters"[!-~]|([!-~][ -~]*[!-~])" -It is meant to signify that String does not start or end with white spaces.Earlier we were to give two different messages when the string would not match any, so I handled like below :
Pattern pattern1 = Pattern.compile("^(.{1,5})?$");
Pattern pattern2 = Pattern.compile("[!-~]|([!-~][ -~]*[!-~])");
Matcher matcher1=pattern1.matcher(" verify");
Matcher matcher2 = pattern2.matcher("verify");
System.out.println("Message1 - " + matcher1.matches());
System.out.println("Message2 - " + matcher2.matches());
But now the requirement is that we need to : --We need to club both the above patterns BUT
--Also include that the string can contain the following characters $, #,@ other than letters, number
--And give one single message.
I looked on many similiar questions asked like: regex for no whitespace at the begining and at the end but allow in the middle and https://regex101.com/ to make a single regex like :
Pattern pattern3=Pattern.compile(
"^[^\\\s][[-a-zA-Z0-9-()@#$]+(\\\s+[-a-zA-Z0-9-()@#$]+)][^\\\s]{1,50}$");
But the regex is not working correctly. If I provide a string with a character other than mentioned in the regex like '%' it should have failed but it passed.
I am trying to figure out that what is problem in the above regex or any new regex which can fulfil the need.
@edit to be more clear: Valid input : "Hell@"
Invalid input : " Hell" (have whitepace @beginning)
Invalid input : "Hell%" conatins not required char '%'
You may use this regex:
^(?!\s)[a-zA-Z\d$#@ ]{1,5}(?<!\s)$
RegEx Details:
^: Start(?!\s): Negative lookahead, don't allow space at start[a-zA-Z\d$#@ ]{1,5}: Allow these character between 1 to 5 in length(?<!\s): Negative lookbehind, don't allow space before end$: End