apollo-common/src/main/java/com/ctrip/framework/apollo/common/utils/BeanUtils.java/BeanUtils/getProperty
class BeanUtils:  public static Object getProperty(Object obj, String fieldName) {
    try {
      Field field = deepFindField(obj.getClass(), fieldName);
      if (field != null) {
        field.setAccessible(true);
        return field.get(obj);
      }
    } catch (Exception e) {
      throw new BeanUtilsException(e);
    }
    return null;
  }