python实现单例模式

class SingletonType(type):

def __init__(self,*args,**kwargs):

    super(SingletonType,self).__init__(*args,**kwargs)



def __call__(cls, *args, **kwargs): # 这里的cls，即Foo类

    print('cls',cls)

    obj = cls.__new__(cls,*args, **kwargs)

    cls.__init__(obj,*args, **kwargs) # Foo.__init__(obj)

    return obj

class Foo(metaclass=SingletonType): # 指定创建Foo的type为SingletonType

def __init__(self，name):

    self.name = name

def __new__(cls, *args, **kwargs):

    return object.__new__(cls)

obj = Foo('xx')

来源：https://www.cnblogs.com/zhaogang0104/p/11938683.html