Java tutorial
//package com.java2s; //License from project: Open Source License import java.util.regex.*; public class Main { public static final Pattern regex_ws = Pattern.compile("\\s+"), regex_csv = Pattern.compile("\\s*(,\\s*)+"), regex_norm = Pattern.compile("[^a-z_0-9\\Q-_+,.\\E]+"), regex_path = Pattern.compile("[^^]/+"); public static String normalize(String s) { if (s == null) return ""; s = s.toLowerCase(); s = regex_norm.matcher(s).replaceAll(" ").trim(); s = regex_ws.matcher(s).replaceAll("_"); return s; } }