code: @JSONField(serialize = false, deserialize = false)
    public void setMentionListString(String content) {
      if (StringUtil.isEmpty(content)) {
        this.mentionList = null;
      } else {
        this.mentionList = new ArrayList<>();
        String[] peerIdArray = content.split("[,\\s]");
        for (String peer: peerIdArray) {
          if (!StringUtil.isEmpty(peer)) {
            this.mentionList.add(peer);
          }
        }
      }
    }
docs: 设置 mention 用户列表字符串（逗号分隔），功能与 #setMentionList(List<String> peerIdList) 相同，两者调用一个即可。
  @param content