Python 单例

方法1：

 1 class Singleton(object):
     def __new__(cls, *args, **kwargs):
         if '_inst' not in vars(cls):
             cls._inst = super(Singleton, cls).__new__(cls, *args, **kwargs)
         return cls._inst

     def __init__(self):
         print "init"

 class SingleSpam(Singleton):
     def __init__(self, s):
         self.s = s
         print "creat"

方法2：

def sinaleton(cls, *arg, **kwargs):
    # print cls
    isin = {}
    def __single():
        print isin
        if cls not in isin:
            isin[cls] = type(cls, *arg, **kwargs)
        return isin[cls]
    return __single

@sinaleton
class myclass(object):
    pass