public static String changeCharset(String str, String defaultValue)
    {
        if (str != null)
        {
            
            try
            {
                if ((StringUtils.isNotBlank(str)) && str.equals(
                        new String(str.getBytes("ISO-8859-1"), "ISO-8859-1")))
                {
                    return new String(str.getBytes("ISO-8859-1"), "UTF-8");
                }
                return str;
            }
            catch (UnsupportedEncodingException e)
            {
                throw new RuntimeException("字符串转换异常！！！！");
                
            }
        }
        return defaultValue;
    }