python_并发编程——数据共享

1.数据共享

　　实现进程之间的数据共享

from multiprocessing import Manager,Process
class MyPro(Process):
    def __init__(self,dic):
        super().__init__()
        self.dic = dic
    def run(self):
        self.dic['count'] -= 1
        print(self.dic)


if __name__ == '__main__':
    m = Manager()
    dic = m.dict({'count':100})
    p = MyPro(dic)
    p.start()
    p.join()
    print('主进程：',dic)

结果：　　　　

2.但是这种数据共享还是存中安全性问题，当有多个进程同时访问数据的时候，还是会出错，当应用在有多个进程的时候，还是要加锁。

from multiprocessing import Manager,Process,Lock
class MyPro(Process):
    def __init__(self,dic,lock):
        super().__init__()
        self.dic = dic
        self.lock = lock
    def run(self):
        self.lock.acquire()
        self.dic['count'] -= 1
        self.lock.release()
        # print(self.dic)


if __name__ == '__main__':
    lock = Lock()
    m = Manager()
    dic = m.dict({'count':100})
    p_list = []
    for i in range(50):
        p = MyPro(dic,lock)
        p.start()
        p_list.append(p)
    for i in p_list:
        p.join()
    print('主进程:',dic)

结果：