Subject: Regular expression examples
Author: Alex_Raj
In response to: Lookahead assertion examples
Posted on: 08/13/2015 11:26:47 PM
Example: Ipv4 address
String REGEX_IPv4 = "(25[0-5]|2[0-4][0-9]|[0-1][0-9]{2}|[1-9][0-9]|[1-9])" +
"\\." +
"(25[0-5]|2[0-4][0-9]|[0-1][0-9]{2}|[1-9][0-9]|[1-9]|0)" +
"\\." +
"(25[0-5]|2[0-4][0-9]|[0-1][0-9]{2}|[1-9][0-9]|[1-9]|0)" +
"\\." +
"(25[0-5]|2[0-4][0-9]|[0-1][0-9]{2}|[1-9][0-9]|[0-9])";
String REGEX_IPv6 = "(?i)" + "[[a-f][0-9]:/.+*%\\[\\]]+";
String REGEX_EMAIL = "[a-zA-Z0-9_+.%\\-]{1,256}" +
"\\@" +
"[a-zA-Z0-9][a-zA-Z0-9\\-]{0,64}" +
"(" +
"\\.[a-zA-Z0-9][a-zA-Z0-9\\-]{0,25}" +
")+";
String WEB_URL = "(?i)" +
"\\b(https?|ftp|file)://" +
"[a-zA-Z0-9+&@#/%?=~_|!:,.;\\-]*[a-zA-Z0-9+&@#/%=~_|\\-]";
The password strength criteria requires:
8+ characters length
1+ Special Character
1+ letters in Upper Case
2+ numerals (0-9)
3+ letters in Lower Case
String REGEX_PWD =
"^" + // starting
"" + // empty string
"(?=.*[\\W])" + // followed by at least 1 special char
"(?=.*[A-Z])" + // followed by at least 1 upper-case char
"(?=.*[0-9].*[0-9])" + // followed by at least 2 digits
"(?=.*[a-z].*[a-z].*[a-z])" + // followed by at least 3 lower-case chars
".{8,}" + // followed by any (.) chars with total length of at least 8
"$"; // ending
>
> On 08/13/2015 07:16:49 PM
Alex_Raj wrote:
Example: Find empty string '' which is immediately followed by lower-case character
String regex = "(?=[a-z])";
String input = "123a567b9";
System.out.println("Regex: " + regex);
System.out.println("Input: " + input);
Pattern pattern = Pattern.compile(regex);
Matcher matcher = pattern.matcher(input);
boolean found = false;
while (matcher.find()) {
System.out.println("Found '" + matcher.group() +
"' from " + matcher.start() +
" to " + matcher.end());
found = true;
}
if(!found)
System.out.println("No match found!");
The ouput:
Regex: (?=[a-z])
Input: 123a567b9
Found '' from 3 to 3
Found '' from 7 to 7
Example: Find string which 1) starts with '' and 2) is immediately followed by lower-case character and 3) has total length of 2 any characters
String regex = "(?=[a-z]).{2}";
String input = "123a567b9";
The ouput:
Regex: (?=[a-z]).{2}
Input: 123a567b9
Found 'a5' from 3 to 5
Found 'b9' from 7 to 9
Example: Find string which 1) starts with '' and 2) is immediately followed by lower-case character and 3) has total length of 3 any characters
String regex = "(?=[a-z]).{3}";
String input = "123a567b9";
The ouput:
Regex: (?=[a-z]).{3}
Input: 123a567b9
Found 'a56' from 3 to 6
References:
