public static String isNullOrEmpty(String str) {
        if (StringUtils.isEmpty(str) || EMPTY_STR.equals(str)) {
            return "";
        }
        return str;
    }
How to deal with initial letters
chat2db-server/chat2db-server-web/chat2db-server-web-api/src/main/java/ai/chat2db/server/web/api/util/StringUtils.java