code
# 文件db的内容为：{"count":5}
# 注意一定要用双引号，不然json无法识别
# 并发运行，效率高，但竞争写同一文件，数据写入错乱
from multiprocessing import Process,Lock import time,json,random def search(): dic=json.load(open('db')) print('剩余票数%s' %dic['count']) def get(): dic=json.load(open('db')) time.sleep(random.random()) # 模拟读数据的网络延迟 if dic['count'] >0: dic['count']-=1 time.sleep(random.random()) # 模拟写数据的网络延迟 json.dump(dic,open('db','w')) print('购票成功') else: print('购票失败') def task(lock): search() lock.acquire() get() lock.release() if __name__ == '__main__': lock = Lock() for i in range(100): # 模拟并发100个客户端抢票 p=Process(target=task,args=(lock,)) p.start()
outputs
macname@MacdeMacBook-Pro py % python3 cccccc.py
剩余票数2
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购票成功
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macname@MacdeMacBook-Pro py %