/**
     * list 转 string 逗号拼接
     */
    public static String listToString(List<String> list) {
        if (list == null) {
            return null;
        }
        return String.join(",", list);
    }

    /**
     * string 转 list
     */
    public static List<String> stringToList(String strs) {
        return Arrays.asList(strs.split(","));
    }