类的装饰器

 1 def demo(obj):
 2     print(‘===================‘)
 3     obj.x = 1
 4     obj.y = 2
 5     obj.z = 3
 6     return obj
 7 
 8 @demo
 9 class Foo:
10     pass
11 
12 f1 = Foo()
13 print(Foo.__dict__)
14 输出：
15 ===================
16 {‘__module__‘: ‘__main__‘, ‘__dict__‘: <attribute ‘__dict__‘ of ‘Foo‘ objects>, ‘__weakref__‘: <attribute ‘__weakref__‘ of ‘Foo‘ objects>, ‘__doc__‘: None, ‘x‘: 1, ‘y‘: 2, ‘z‘: 3}

 1 def demo(obj):
 2     print(‘===================‘)
 3     obj.x = 1
 4     obj.y = 2
 5     obj.z = 3
 6     return obj
 7 @demo
 8 def test():
 9     print(‘这是个测试函数‘)
10 test()
11 print(test.__dict__)
12 输出：
13 ===================
14 这是个测试函数
15 {‘x‘: 1, ‘y‘: 2, ‘z‘: 3}

 1 def test(**kwargs):
 2     def wrapper(obj):
 3         for key, val in kwargs.items():
 4             setattr(obj, key, val)
 5         return obj
 6 
 7     return wrapper
 8 
 9 
10 @test(a=1, b=2)  # @wrapper
11 class Foo:
12     def __init__(self, name):
13         self.name = name
14 
15 
16 print(Foo.__dict__)
17 输出：
18 {‘__module__‘: ‘__main__‘, ‘__init__‘: <function Foo.__init__ at 0x00000000024C3280>, ‘__dict__‘: <attribute ‘__dict__‘ of ‘Foo‘ objects>, ‘__weakref__‘: <attribute ‘__weakref__‘ of ‘Foo‘ objects>, ‘__doc__‘: None, ‘a‘: 1, ‘b‘: 2}