单例模式

单例，顾名思义单个实例。

class Person:
    __instance = None
    def __init__(self):
        pass
    @staticmethod
    def getInstance():
        if Person.__instance:
            return Person.__instance
        else:
            Person.__instance = Person()
            return Person.__instance
obj1 = Person.getInstance()
print(obj1)
obj2 = Person.getInstance()
print(obj2)
##################################################
<__main__.Person object at 0x0088A2D0>
<__main__.Person object at 0x0088A2D0>