生产者、消费者问题，python实现

生产者、消费者问题，经典的线程同步问题：假设有一个缓冲池(列表)，生产者往里面放东西，消费者从里面取，规则是：列表为空的时候，生产者才能放东西；列表不为空的时候，消费者才能取东西；为了简单起见，暂定缓冲池中最多只能有一个产品。这里生产者和消费者共同操作一个资源：缓冲池，因此每次操作的时候，需要给资源加锁，操作结束时，释放锁，这样才能做到资源同步。使用python实现，需要继承Thread类，获取锁对象，代码如下：

from threading import Thread

from threading import Lock

import time,random

pro_list = []

lock = Lock()

class Producer(Thread):

def run(self):

global pro_list

while True:

i = random.randint(0, 100)

lock.acquire()

if len(pro_list) > 0:

print "!--product still in list, wait consumer to get it.."

else:

pro_list.append(i)

print ":::Producer put:", pro_list[0]

lock.release()

time.sleep(2)

class Consumer(Thread):

def run(self):

global pro_list

while True:

lock.acquire()

if len(pro_list) == 0:

print "!--No product now, wait producer put in..."

else:

print ":::Consumer fetch:", pro_list[0]

pro_list.pop(0)

lock.release()

time.sleep(2)

Producer().start()

Producer().start()

Consumer().start()

Producer().start()

Producer().start()

Consumer().start()

Consumer().start()

这里使用多个生产者和消费者，共同操作缓冲池，部分执行结果如下：

:::Producer put: 12

!--product still in list, wait consumer to get it..

:::Consumer fetch: 12

:::Producer put: 75

!--product still in list, wait consumer to get it..

:::Consumer fetch: 75

!--No product now, wait producer put in...

:::Producer put: 28

!--product still in list, wait consumer to get it..

!--product still in list, wait consumer to get it..

:::Consumer fetch: 28

:::Producer put: 94

:::Consumer fetch: 94