python - Django try/except on DoesNotExist 仍然抛出它

Question

我正在努力解决我的应用程序中的 DoesNotExist 错误。关键是我真的不明白为什么会抛出这个错误，因为我已经处理过了:

import socket

from django.core.exceptions import ObjectDoesNotExist
from django.db import Models

class MyClass(models.Model):
    name = models.CharField(max_length=250, default=socket.gethostname(), unique=True)
    @staticmethod
    def update_some_list(some_list):
        for some_item in some_list:
            try:
                MyClass.objects.get(name=some_item)
            except ObjectDoesNotExist:  # I also tried with MyClass.DoesNotExist
                MyClass.objects.create(name=some_item)

这里的重点是，当我遇到这段代码时，我有一些被丢弃的“模块级”DoesNotExist，就好像这个 try/except block 永远不会被命中:

Traceback (most recent call last):
  File "/app/backend/shared/models.py", line 201, in update_some_list
    MyClass.objects.get(name=some_item)
  File "/usr/lib/python3.6/site-packages/django/db/models/manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/usr/lib/python3.6/site-packages/django/db/models/query.py", line 399, in get
    self.model._meta.object_name
shared.models.DoesNotExist: MyClass matching query does not exist.

Answer 1

考虑使用 QuerySet.get_or_create ，这将消除上述问题。

MyClass.objects.get_or_create(name=some_item)

此外，请注意，如果您访问 @staticmethod 中的类将其更新为 @classmethod 是有意义的.另外，在您遇到的问题中:

from django.db import Models

代替 从 django.db 导入模型