python 实现单例模式的5种方法

一、classmethod装饰器 # 全局变量 ip = '192.168.13.98' port = '3306' class MySQL: __instance = None def __init__(self, ip, port): self.ip = ip self.port = port @classmethod def instance(cls, *args, **kwargs): if args or kwargs: cls.__instance = cls(*args, **kwargs) return cls.__