Question

I’ve got the regexes working in Javascript, now I want to translate these to Java:

            var nat_pattern2 = /^\d{8}$/;
            var nat_pattern2 = /^\d{7}\-\d{1}$/;

            var pct_pattern1 = /^\PCT\/?[A-Z]{2}?\d{4}\/\d{6}$/;
            var ing pct_pattern2 = /^\PCT[A-Z]{2}\d{10}$/;
            var pct_pattern3 = /^\P[A-Z]{2}\d{8}$/;

            var its_pattern1 = /^\ITS\/?[A-Z]{2}?\d{2}\/\d{5}$/;
            var its_pattern2 = /^\ITS[A-Z]{2}\d{7}$/;
            var its_pattern3 = /^\I[A-Z]{2}\d{7}$/;

My beginning looks something like this but it is not correct:

Pattern pattern = Pattern.compile("/^\d{8}$/");

Can you help me?

Answer 1

You don’t need the / around your regexp in Java. \d as to be escaped in order to be part of the String defining the regex so it will become \\d.

Pattern pattern = Pattern.compile("^\\d{8}$");

Slashes have no special meanings and so don’t need to be escaped too.

Pattern natPattern1 = Pattern.compile("^\\d{8}$");
Pattern natPattern2 = Pattern.compile("^\\d{7}-\\d{1}$");

Pattern pctPattern1 = Pattern.compile("^PCT/?[A-Z]{2}?\\d{4}/\\d{6}$");
Pattern pctPattern2 = Pattern.compile("^PCT[A-Z]{2}\\d{10}$");
Pattern pctPattern3 = Pattern.compile("^P[A-Z]{2}\\d{8}$");

Pattern itsPattern1 = Pattern.compile("^ITS/?[A-Z]{2}?\\d{2}/\\d{5}$");
Pattern itsPattern2 = Pattern.compile("^ITS[A-Z]{2}\\d{7}$");
Pattern itsPattern3 = Pattern.compile("^I[A-Z]{2}\\d{7}$");