Python 实现单例模式
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 | # 使用Python实现单例模式 # 方法一: 使用__new__方法 class SingleTon( object ): def __new__( cls , * args, * * kwargs): if not hasattr ( cls , '_instance' ): cls ._instance = object .__new__( cls , * args, * * kwargs) return cls ._instance class TestClass(SingleTon): a = 1 # 方法二: 使用装饰器(decorator) def SingleTon1( cls , * args, * * kwargs): instances = {} def _singleTon(): if cls not in instances: instances[ cls ] = cls ( * args, * * kwargs) return instances[ cls ] return _singleTon @SingleTon1 class TestClass1( object ): a = 1 # 共享属性 属性是共享的,但是并非单例模式 class SingleTon3( object ): _state = {} def __new__( cls , * args, * * kwargs): obj = object .__new__( cls , * args, * * kwargs) obj.__dict__ = cls ._state return obj class TestClass3(SingleTon3): a = 1 test1 = TestClass3() test2 = TestClass3() test1.a = 2 print (test1.a) print (test2.a) print (test1) print (test2) |
本文转自 许大树 51CTO博客，原文链接：http://blog.51cto.com/abelxu/1967293，如需转载请自行联系原作者
