code: private static XmlElement generateTrim(boolean bracket) {
          XmlElement trimEle = new XmlElement("trim");
          if (bracket) {
              trimEle.addAttribute(new Attribute("prefix", "("));
              trimEle.addAttribute(new Attribute("suffix", ")"));
              trimEle.addAttribute(new Attribute("suffixOverrides", ","));
          } else {
              trimEle.addAttribute(new Attribute("suffixOverrides", ","));
          }
          return trimEle;
      }
docs: trim 节点
  @param bracket
  @return