重写new方法
# coding=utf-8
class Singleton(object):
def __new__(cls, *args, **kwargs):
if not hasattr(cls, '_instance'):
cls._instance = super(Singleton, cls).__new__(cls, *args, **kwargs)
return cls._instance
class MyClass(Singleton):
a = 1
one = MyClass()
two = MyClass()
print(id(one))
print(id(two))
装饰器版本
# coding=utf-8
def singleton(cls, *args, **kw):
instances = {}
def getinstance():
if cls not in instances:
instances[cls] = cls(*args, **kw)
return instances[cls]
return getinstance
@singleton
class MyClass(object):
a = 1
one = MyClass()
two = MyClass()
print(id(one))
print(id(two))
import导入
# mysingleton.py
class My_Singleton(object):
def foo(self):
pass
my_singleton = My_Singleton()
# to use
from mysingleton import my_singleton
my_singleton.foo()
