code: public static XmlTypeConvert resolve(XmlNode attrXmlNode,
                                           BeanUtils.CustomPropertyDescriptor filed) {
          XmlTypeConvert convert;
          if (attrXmlNode != null) {
              Class<? extends XmlTypeConvert> fieldConverterClass;
              fieldConverterClass = attrXmlNode.converter();
              //判断用户是否指定converter
              if (XmlTypeConvert.class.equals(fieldConverterClass)) {
                  //用户没有指定converter
                  convert = resolve(filed);
              } else {
                  try {
                      convert = fieldConverterClass.newInstance();
                  } catch (Exception e) {
                      convert = resolve(filed);
                      logger.warn("指定的xml转换器[{}]无法实例化，请为该转换器增加公共无参数构造器，当前将使用默认转换器[{}]",
                          fieldConverterClass, convert.getClass(), e);
                  }
              }
          } else {
              convert = resolve(filed);
          }
          return convert;
      }
docs: 确定converter
  
  @param attrXmlNode 字段的注释
  @param filed       字段说明
  @return 字段对应的converter