code: private static ExcelConfig getEasyExcel(String xmlPath) {
          ExcelConfig easyExcel = cache.get(xmlPath);
          if (easyExcel == null) {
              easyExcel = XmlConfig.getXmlConfig(xmlPath);
          }
          if (easyExcel == null) {
              throw new RuntimeException("无法获取xml配置文件!");
          }
          if (easyExcel.getCache() == null || easyExcel.getCache()) {
              cache.put(xmlPath, easyExcel);
          }
          return easyExcel;
      }
docs: 获取xml配置对象
  
  @param xmlPath xml完整路径
  @return xml配置对象