code: public static int getPageSize() {
      String pageSize = Params.get(PAGESIZE);
      int pagesize = Page.DEFAULT_PAGE_SIZE;
      if (Strings.isNotBlank(pageSize)) {
        pagesize = Numbers.toInt(pageSize.trim());
      } else {
        HttpServletRequest request = ServletActionContext.getRequest();
        pageSize = CookieUtils.getCookieValue(request, PAGESIZE);
        if (Strings.isNotEmpty(pageSize)) pagesize = Numbers.toInt(pageSize);
      }
      if (pagesize < 1) pagesize = Page.DEFAULT_PAGE_SIZE;
      return pagesize;
    }
docs: 获得请求中的页长