Question

I use RegexBuddy while working with regular expressions. From its library I copied the regular expression to match URLs. I tested successfully within RegexBuddy. However, when I copied it as Java String flavor and pasted it into Java code, it does not work. The following class prints false:

public class RegexFoo {      public static void main(String[] args) {         String regex = '\\b(https?|ftp|file)://[-A-Z0-9+&@#/%?=~_|!:,.;]*[-A-Z0-9+&@#/%=~_|]';         String text = 'http://google.com';         System.out.println(IsMatch(text,regex)); }      private static boolean IsMatch(String s, String pattern) {         try {             Pattern patt = Pattern.compile(pattern);             Matcher matcher = patt.matcher(s);             return matcher.matches();         } catch (RuntimeException e) {         return false;     }        }    } 

Does anyone know what I am doing wrong?

Answer 1

Try the following regex string instead. Your test was probably done in a case-sensitive manner. I have added the lowercase alphas as well as a proper string beginning placeholder.

String regex = '^(https?|ftp|file)://[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|]'; 

This works too:

String regex = '\\b(https?|ftp|file)://[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|]'; 

Note:

String regex = '<\\b(https?|ftp|file)://[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|]>'; // matches <http://google.com>  String regex = '<^(https?|ftp|file)://[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|]>'; // does not match <http://google.com>