驼峰式命名法

    /**
     * 驼峰式命名法 例如：user_name->userName
     * 
     * @param s
     * @return
     */
    public static String toCamelCase(String s) {
        if (s == null) {
            return null;
        }

        s = s.toLowerCase();
        StringBuilder sb = new StringBuilder(s.length());
        boolean upperCase = false;
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            if (c == '_') {
                upperCase = true;
            } else if (upperCase) {
                sb.append(Character.toUpperCase(c));
                upperCase = false;
            } else {
                sb.append(c);
            }
        }

        return sb.toString();
    }