#coding=utf-8import threading, time#整个try的这一段其实就是定义了一个装饰器 make_synchronizedtry: from synchronize import make_synchronizedexcept ImportError: def make_synchronized(func): func.__lock__ = threading.Lock() def synced_func(*args, **kws): #with 会自动给threading.Lock 获取锁和释放锁（资源） with func.__lock__: return func(*args, **kws) #锁定期间， 其他线程获取不到资源 return synced_funcclass Singleton(object): instance = None @make_synchronized def __new__(cls, *args, **kwargs): #__new___ 本身用来初始化实例， 如果check 到内存中有初始化的实例则直接返回内存地址 #如果check到没有实例化的实例则调用父类的__new__重新进行初始化实例， 之所以说调用父类的__new__ #是因为我们实际上是重载了object的__new__ #__new__的返回就是__init__中的self值 if cls.instance is None: cls.instance = object.__new__(cls, *args, **kwargs) #cls.instance = super(Singleton, cls).__new__(cls, *args, **kwargs) 这两段代码同等作用 return cls.instance def __init__(self): #time.sleep(1) self.blog = "brownz" def go(self): #定义全局变量， 所有线程均可调用 global num for i in xrange(1000000): num += 1 print "go num is:", num, time.time()def worker(): e = Singleton() print e.blog print id(e) e.go()def test(): e1 = Singleton() e2 = Singleton() e1.blog = 123 print e1.blog print e2.blog print id(e1) print id(e2)if __name__ == "__main__": test() task = [] num = 0 for i in range(3): t = threading.Thread(target=worker()) task.append(t) t.start() for threadlist in task: threadlist.join()
[out]:
:\Project-workspace\python_test\Thread>python singleton.py
1231234036526440365264brownz40365264go num is: 1000000 1536060468.22brownz40365264go num is: 2000000 1536060468.3brownz40365264go num is: 3000000 1536060468.38
windows下面看不出上不上锁的区别， 自行理解多线程的上锁机制吧