Here you can find the source of toUnderscore(String s)
public static String toUnderscore(String s)
//package com.java2s; /*//from w w w.j a v a 2s . c o m * ==================================================================== * Copyright (c) 1995-1999 Purple Technology, Inc. All rights * reserved. * * PLAIN LANGUAGE LICENSE: Do whatever you like with this code, free * of charge, just give credit where credit is due. If you improve it, * please send your improvements to alex@purpletech.com. Check * http://www.purpletech.com/code/ for the latest version and news. * * LEGAL LANGUAGE LICENSE: Redistribution and use in source and binary * forms, with or without modification, are permitted provided that * the following conditions are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following * disclaimer in the documentation and/or other materials provided * with the distribution. * * 3. The names of the authors and the names "Purple Technology," * "Purple Server" and "Purple Chat" must not be used to endorse or * promote products derived from this software without prior written * permission. For written permission, please contact * server@purpletech.com. * * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND PURPLE TECHNOLOGY ``AS * IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * AUTHORS OR PURPLE TECHNOLOGY BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED * OF THE POSSIBILITY OF SUCH DAMAGE. * * ==================================================================== * **/ public class Main { /** * Converts camelCaseVersusC to camel_case_versus_c **/ public static String toUnderscore(String s) { StringBuffer buf = new StringBuffer(); char[] ch = s.toCharArray(); for (int i = 0; i < ch.length; ++i) { if (Character.isUpperCase(ch[i])) { buf.append('_'); buf.append(Character.toLowerCase(ch[i])); } else { buf.append(ch[i]); } } //System.err.println(s + " -> " + buf.toString()); return buf.toString(); } }