python3 基於原語鎖的簡單同步__python

１、簡單的銀行提款程式：

import threading ,time,randomclass Account(threading.Thread):lock=threading.Lock();def __init__(self,amount):threading.Thread.__init__(self)Account.amount=amountdef run (self):self.withdraw()def withdraw(self):Account.lock.acquire()t=threading.current_thread()a=random.choice(range(50,101))if(Account.amount<a):print('{0}交易失敗，取款前金額為{1}，取款金額{2}'.format(t.name,Account.amount,a))Account.lock.release()return 0time.sleep(random.choice(range(5)))prev = Account.amountAccount.amount -= aprint('{0}取款前金額為{1}，取款金額{2}，取款後金額{3}'.format(t.name,prev,a,Account.amount))Account.lock.release()def test():for i in range(5):Account(200).start()if __name__=='__main__':test()

此程式通過對象鎖實現同步，比較容易產生死結，所以對其進行改進。

import threading,time,randomclass Container1():def __init__(self):self.contents=0self.available=Falseself.cv=threading.Condition()def put(self,value):with self.cv:if self.available:self.cv.wait()self.contents=valuet=threading.current_thread()print('{0}生產{1}'.format(t.name,self.contents))self.available=Trueself.cv.notify()def get(self):with self.cv:if not self.available:self.cv.wait()t=threading.current_thread()print('{0}消費{1}'.format(t.name,self.contents))self.available=Falseself.cv.notify()class Producer(threading.Thread): def __init__(self,container): threading.Thread.__init__(self) self.container=container def run(self): for i in range(1,6): time.sleep(random.choice(range(5))) self.container.put(i)class Consumer(threading.Thread): def __init__(self,container): threading.Thread.__init__(self) self.container=container def run(self): for i in range(1,6): time.sleep(random.choice(range(5))) self.container.get()def test(): print('基本同步和通訊的生產者消費者模型：') container=Container1() Producer(container).start() Consumer(container).start()if __name__=='__main__' : test()