互斥锁之模拟抢票

import time, json
from multiprocessing import Process, Lock  #  互斥锁
def serch(name):
    time.sleep(1)
    dic = json.load(open('db.txt', 'r', encoding='utf-8'))
    print('%s查看到剩余票数是%s'%(name, dic['count']))
def get(name):
    dic = json.load(open('db.txt', 'r', encoding='utf-8'))
    if dic['count'] > 0:
        dic['count'] -= 1
        time.sleep(3)
        json.dump(dic, open('db.txt', 'w', encoding='utf-8'))
        print('%s抢票成功！'%name)
def task(name, mutex):
    serch(name)
    mutex.acquire()  #开启互斥锁
    get(name)
    mutex.release()  #关闭互斥锁
if __name__ == '__main__':
    mutex = Lock()  #互斥锁实例化
    for i in range(10):
        p = Process(target=task, args=('路人%s'%i, mutex))   #运用到子进程中一定要从父进程传入‘mutex’否则子进程会重新实例化互斥锁
        p.start()
#互斥锁的的意义是只能单个进程进行，所以有开启互斥锁也就又关闭互斥锁的机制