本文实例为大家分享了python单例模式的具体代码，供大家参考，具体内容如下
多次实例化的结果指向同一个实例
单例模式实现方式
方式一:
import settingsclass MySQL: __instance = None def __init__(self, ip, port): self.ip = ip self.port = port @classmethod def from_conf(cls): if cls.__instance is None: cls.__instance = cls(settings.IP,settings.PORT) return cls.__instanceobj1 = MySQL.from_conf()obj2 = MySQL.from_conf()obj3 = MySQL.from_conf()print(obj1)print(obj2)print(obj3)
方式二:
import settingsdef singleton(cls): _instance = cls(settings.IP, settings.PORT) def wrapper(*args, **kwargs): if args or kwargs: obj = cls(*args, **kwargs) return obj return _instance return wrapper@singletonclass MySQL: def __init__(self, ip, port): self.ip = ip self.port = portobj1 = MySQL()obj2 = MySQL()obj3 = MySQL()print(obj1)print(obj2)print(obj3)
方式三:
import settingsclass Mymeta(type): def __init__(self, class_name, class_bases, class_dic): self.__instance = self(settings.IP, settings.PORT) def __call__(self, *args, **kwargs): if args or kwargs: obj = self.__new__(self) self.__init__(obj, *args, **kwargs) return obj else: return self.__instanceclass MySQL(metaclass=Mymeta): def __init__(self, ip, port): self.ip = ip self.port = portobj1 = MySQL()obj2 = MySQL()obj3 = MySQL()print(obj1)print(obj2)print(obj3)
方式四:
def f1(): from singleton import instance print(instance)def f2(): from singleton import instance,MySQL print(instance) obj = MySQL('1.1.1.1', '3389') print(obj)f1()f2()singleton.py文件里内容:import settingsclass MySQL: print('run...') def __init__(self, ip, port): self.ip = ip self.port = portinstance = MySQL(settings.IP, settings.PORT) 以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持VEVB武林网。
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