Regular expression to match URLs in Java

java, regex, regexbuddy

Solution

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>

Problem

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?

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