private String buildExtParamByParentTag(final TagDO parentTagDO) {
        String ext = "";
        if (parentTagDO.getId().equals(AdminConstants.TAG_ROOT_PARENT_ID)) {
            final TagDO.TagExt parent = new TagDO.TagExt();
            TagDO.TagExt tagExt = new TagDO.TagExt();
            tagExt.setDesc(parentTagDO.getTagDesc());
            tagExt.setName(parentTagDO.getName());
            tagExt.setId(parentTagDO.getId());
            tagExt.setRefreshTime(parent.getRefreshTime());
            tagExt.setApiDocMd5(parent.getApiDocMd5());
            parent.setParent(tagExt);
            ext = GsonUtils.getInstance().toJson(parent);
        } else {
            TagDO.TagExt parentTagExt = Optional.ofNullable(GsonUtils.getInstance().fromJson(parentTagDO.getExt(), TagDO.TagExt.class)).orElse(new TagDO.TagExt());
            final TagDO.TagExt tagExt = new TagDO.TagExt();
            parentTagExt.setDesc(parentTagDO.getTagDesc());
            parentTagExt.setName(parentTagDO.getName());
            parentTagExt.setId(parentTagDO.getId());
            tagExt.setParent(parentTagExt);
            ext = GsonUtils.getInstance().toJson(tagExt);
        }
        return ext;
    }
buildExtParam.

@param parentTagDO parentTagDO
@return ext
shenyu-admin/src/main/java/org/apache/shenyu/admin/service/impl/TagServiceImpl.java