1. public static String humpToLine2(String str) {
    2.         Matcher matcher = humpPattern.matcher(str);
    3.         StringBuffer sb = new StringBuffer();
    4.         while (matcher.find()) {
    5.             matcher.appendReplacement(sb, "_" + matcher.group(0).toLowerCase());
    6.         }
    7.         matcher.appendTail(sb);
    8.         return sb.toString();
    9.     }
    11.     private final static Pattern humpPattern = Pattern.compile("[A-Z]");