如何解决我们如何通过扩展类将 Python 中的抽象方法和自定义异常结合起来?
有没有好的方法使用abstractmethod?我担心人们仍然可以实例化 class InvalidRequestError
的对象,但我没想到会发生这种情况?
场景 - 1
from http import HTTPStatus
from abc import ABC,abstractmethod
class BaseError(ABC,Exception): # Is it a good idea to subclass the Exception's class as well ?
pass
class RequestError(BaseError,ABC):
@abstractmethod
def STATUS_CODE(self):
raise NotImplementedError
class InvalidRequestError(RequestError):
STATUS_CODE = HTTPStatus.BAD_REQUEST
# InvalidRequestError() # I was expecting it to raise an error but it didn't.
场景 - 2
from http import HTTPStatus
from abc import ABC,abstractmethod
class BaseError(ABC):
pass
class RequestError(BaseError,ABC):
@abstractmethod
def STATUS_CODE(self):
raise NotImplementedError
class InvalidRequestError(RequestError):
STATUS_CODE = HTTPStatus.BAD_REQUEST
InvalidRequestError() # runs
但这如我所料,(它引发了追溯)
import abc
class BaseError(abc.ABC):
pass
class GeneralError(BaseError):
@abc.abstractmethod
def something(self):
raise NotImplementedError
class Test(GeneralError):
pass
# test() # raises the exception I was looking for; TypeError: Can't instantiate abstract class Test with abstract methods...
# And so does the below,from http import HTTPStatus
from abc import ABC,ABC):
@abstractmethod
def STATUS_CODE(self):
raise NotImplementedError
class InvalidRequestError(RequestError):
pass # STATUS_CODE = HTTPStatus.BAD_REQUEST
# InvalidRequestError() # raises the exception I was looking for; TypeError: Can't instantiate abstract class Test with abstract methods.
与最上面的代码片段相比,在最后一个片段中,我所做的更改不再是继承 Exceptions 类并用 pass 替换 STATUS_CODE 行。
我想了解为什么会发生这种情况以及实现这一目标的更pythonic的方法是什么?
感谢路过;
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