private String escapeHex(String originalString) {
        Matcher matcher = HEX_PATTERN.matcher(originalString);
        StringBuffer sb = new StringBuffer();
        while (matcher.find()) {
            // Replace _xHHHH_ with _x005F_xHHHH_
            matcher.appendReplacement(sb, "_x005F_x" + matcher.group(1) + "_");
        }
        matcher.appendTail(sb);
        return sb.toString();
    }
Escapes hexadecimal-encoded strings
Replaces _xHHHH_ with _x005F_xHHHH_ to prevent POI from decoding them
fastexcel-core/src/main/java/cn/idev/excel/write/handler/EscapeHexCellWriteHandler.java