python基础-单例模式

class Dog(object):
__instance=None

    def __init__(self,name):
            self.name=name
            print("名字叫%s的对象初始化成功..."%(self.name))

    def __str__(self):
            return "这是%s的描述..."%(self.name)

    def __del__(self):
            print("======================================")
            print("Dog对象已回收...")

    def __new__(cls,name):
            if not cls.__instance:
                    cls.__instance=super().__new__(cls)
                    #cls.__instance=object.__new__(cls)
                    print("对象_instance创建成功...")
                    return cls.__instance
            else:
                    print("__instance 对象已创建...")
                    return cls.__instance

dog=Dog("大黄")
print(dog)

print("======================================")

dog2=Dog("旺财")
print(dog2)

print("======================================")

dog2=Dog("啸天犬")
print(dog2)

print("======================================")

dog2=Dog("八公")
print(dog2)