classonlymethod和classmethod區(qū)別
如果要使用classonlymethod ,則需要先定義好一個classonlymethod 類。
首先我們需要明白無論是classonlymethod還是classmethod，本質(zhì)都是一個類，而classonlymethod繼承了classmethod。
classonlymethodz作用:只能被類調(diào)用，不能被實例對象調(diào)用。
class classonlymethod(classmethod): ?# 繼承classmethod
? ?def __get__(self, instance, cls=None): #
? ? ? ?if instance is not None:
? ? ? ? ? ?raise AttributeError("This method is available only on the class, not on instances.")
? ? ? ?return super(classonlymethod, self).__get__(instance, cls)
示例2
from django.utils.decorators import classonlymethod
class Foo:
? ?def __init__(self, name, a = None):
? ? ? ?self.name = name
? ?@classonlymethod
? ?def as_view(cls, actions=None, **initkwargs):
? ? ? ?"""
? ? ? ?Because of the way class based views create a closure around the
? ? ? ?instantiated view, we need to totally reimplement `.as_view`,
? ? ? ?and slightly modify the view function that is created and returned.
? ? ? ?"""
? ? ? ?# The name and description initkwargs may be explicitly overridden for
? ? ? ?# certain route confiugurations. eg, names of extra actions.
? ? ? ?cls.name = None
? ? ? ?cls.description = None
? ? ? ?page = None
? ? ? ?# The suffix initkwarg is reserved for displaying the viewset type.
? ? ? ?# This initkwarg should have no effect if the name is provided.
? ? ? ?# eg. 'List' or 'Instance'.
? ? ? ?cls.suffix = None
? ? ? ?# The detail initkwarg is reserved for introspecting the viewset type.
? ? ? ?cls.detail = None
? ? ? ?# Setting a basename allows a view to reverse its action urls. This
? ? ? ?# value is provided by the router through the initkwargs.
? ? ? ?cls.basename = None
? ? ? ?# actions must not be empty
? ? ? ?if not actions:
? ? ? ? ? ?raise TypeError("The `actions` argument must be provided when "
? ? ? ? ? ? ? ? ? ? ? ? ? ?"calling `.as_view()` on a ViewSet. For example "
? ? ? ? ? ? ? ? ? ? ? ? ? ?"`.as_view({'get': 'list'})`")
? ?def tell(self): ? ?# ?綁定到對象
? ? ? ?print('名字是%s'%self.name)
? ?@classonlymethod
? ?def tell2(cls, page=None): ? ?# ?綁定到對象
? ? ? ?print('@classonlymethod名字是%s'%cls.tell)
? ? ? ?if page is not None:
? ? ? ? ? ?print(page,'page你好啊')
? ?@classmethod ? # ?綁定到類
? ?def func(cls):
? ? ? ?print(cls,'這是classmethod')
? ?@staticmethod ? ?# ?非綁定方法,靜態(tài)方法
? ?def func1(x,y):
? ? ? ?print(x+y)
f = Foo('egon')
print(f,'對象f')
def func3():print('這是函數(shù)func3')
print(Foo.func,'函數(shù)func')
Foo.func()
print('-----------1-----------')
Foo.tell2()
print(Foo.tell2.__module__)
Foo.tell2(123)
print('---------2-------------')
# f.tell2()
Foo.as_view(actions='get')
f.as_view(actions='get') ? ? #
print(Foo.as_view.__module__)
輸出:
Traceback (most recent call last):
?File "D:/python3.64/sss/python_note/面向?qū)ο?21_綁定方法與非綁定方法介紹.py", line 72, in <module>
? ?f.as_view(actions='get') ? ? #
?File "D:\PythonVenv\drf_venv\lib\site-packages\django\utils\decorators.py", line 11, in __get__
? ?raise AttributeError("This method is available only on the class, not on instances.")
AttributeError: This method is available only on the class, not on instances.
<__main__.Foo object at 0x00000228236ED3C8> 對象f
<bound method Foo.func of <class '__main__.Foo'>> 函數(shù)func
<class '__main__.Foo'> 這是classmethod
-----------1-----------
@classonlymethod名字是<function Foo.tell at 0x000002282392C8C8>
__main__
@classonlymethod名字是<function Foo.tell at 0x000002282392C8C8>
123 page你好啊
---------2-------------
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