Python单例模式

day25

单例模式

class Foo:
    __v = None

    @classmethod
    def get_instance(cls):
        if cls.__v:
            return cls.__v
        else:      #  cls.__v = None,创建一个对象
            cls.__v = Foo()
            return cls.__v
#不用使用 类()

obj1 = Foo.get_instance()
print(obj1)
obj2 = Foo.get_instance()
print(obj2)
obj3 = Foo.get_instance()
print(obj3)

只创建一个对象。

执行结果：

<__main__.Foo object at 0x7fa7a75258d0>
<__main__.Foo object at 0x7fa7a75258d0>
<__main__.Foo object at 0x7fa7a75258d0>

Process finished with exit code 0