下划线转驼峰

public static String underline2Camel(String line, boolean smallCamel) {
        if (line == null || "".equals(line)) {
            return "";
        }
        StringBuffer sb = new StringBuffer();
        Pattern pattern = Pattern.compile("([A-Za-z\\d]+)(_)?");
        Matcher matcher = pattern.matcher(line);
        while (matcher.find()) {
            String word = matcher.group();
            sb.append(smallCamel && matcher.start() == 0 ? Character.toLowerCase(word.charAt(0)) : Character.toUpperCase(word.charAt(0)));
            int index = word.lastIndexOf('_');
            if (index > 0) {
                sb.append(word.substring(1, index).toLowerCase());
            } else {
                sb.append(word.substring(1).toLowerCase());
            }
        }
        return sb.toString();
    }