Python--day37--进程锁

进程锁的示意图：

　　锁.py:

 #锁
 #火车票
 import json
 import time

 from multiprocessing import Process
 from multiprocessing import Lock

 def show(i):
     with open('ticket') as f:
         dic = json.load(f)
     print('余票：%s'%dic['ticket'])

 def buy_ticket(i,lock):
     lock.acquire()  #拿钥匙进门
     with open('ticket') as f:
         dic = json.load(f)
         time.sleep(0.1)
     if dic['ticket'] > 0:
         dic['ticket'] -= 1
         print('\033[32m%s买到票了\033[0m'%i)
     else:
         print('\033[31m%s没买到票\033[0m'%i)
     time.sleep(0.1)
     with open('ticket','w') as f:
         json.dump(dic,f)
     lock.release()  #还钥匙

 if __name__ == '__main__':
     for i in range(10):
         p = Process(target=show, args=(i,))
         p.start()
     lock = Lock()
     for i in range(10):
         p = Process(target=buy_ticket, args=(i,lock))
         p.start()

运行结果：