code: private <T> boolean isWithKey(T t, List<Field> fields) {
  		if(t == null || fields == null || fields.isEmpty()) {
  			return false;
  		}
  		
  		List<Field> keyFields = DOInfoReader.getKeyColumns(t.getClass());
  		if(keyFields.isEmpty()) {
  			return false;
  		}
  		
  		for(Field keyField : keyFields) {
  			if(DOInfoReader.getValue(keyField, t) == null) {
  				return false;
  			}
  		}
  		return true;
  	}
docs: 判断对象是否有主键值，必须全部有才返回true