Write code to Return a string with non alphanumeric chars converted to the substitute character.
//package com.book2s; public class Main { public static void main(String[] argv) { String source = "book2s.com"; char substitute = 'a'; System.out.println(toLowerSubset(source, substitute)); }/* w w w . j a v a2 s . c om*/ /** * Returns a string with non alphanumeric chars converted to the * substitute character. A digit first character is also converted. * By sqlbob@users * @param source string to convert * @param substitute character to use * @return converted string */ public static String toLowerSubset(String source, char substitute) { int len = source.length(); StringBuffer sb = new StringBuffer(len); char ch; for (int i = 0; i < len; i++) { ch = source.charAt(i); if (!Character.isLetterOrDigit(ch)) { sb.append(substitute); } else if ((i == 0) && Character.isDigit(ch)) { sb.append(substitute); } else { sb.append(Character.toLowerCase(ch)); } } return sb.toString(); } }