Regular expression to match URLs in Java

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

((http?|https|ftp|file)://)?((W|w){3}.)?[a-zA-Z0-9]+\.[a-zA-Z]+

check here:- https://www.freeformatter.com/java-regex-tester.html#ad-output

It sorts out theses entries correctly

• google.com
• www.google.com
• wwwgooglecom
• ft.
• Www.google.com
• .ft
• https://www.google.com
• https://
• https://www.
• https://google.com

Answer 2

When using regular expressions from RegexBuddy's library, make sure to use the same matching modes in your own code as the regex from the library. If you generate a source code snippet on the Use tab, RegexBuddy will automatically set the correct matching options in the source code snippet. If you copy/paste the regex, you have to do that yourself.

In this case, as others pointed out, you missed the case insensitivity option.