Java tutorial
//package com.java2s; //License from project: Apache License public class Main { /** * Normalizes the phone number format. * * @param number the input phone number. * @return a normalized phone number. */ public static String normalizePhone(String number) { if (number != null && number.length() > 0) { if (number.charAt(0) == '+') { number = "+" + number.substring(1).replaceAll("[^\\d]", ""); return number; } else { number = number.replaceAll("[^\\d]", ""); if (number.length() == 10) return "+1" + number; else if (number.length() == 11 && number.charAt(0) == '1') return "+" + number; else if (number.length() > 10) return "+" + number; else return "+1" + number; } } else { return "+1"; } } }