Python实现的生产者、消费者问题完整实例

本文实例讲述了python实现的生产者、消费者问题。分享给大家供大家参考，具体如下：

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：

# -*- coding:utf-8 -*-
#! python2
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: 78
!--product still in list, wait consumer to get it..
:::consumer fetch: 78
:::producer put: 99
!--product still in list, wait consumer to get it..
:::consumer fetch: 99
!--no product now, wait producer put in...
:::producer put: 12
:::consumer fetch: 12
:::producer put: 91
!--product still in list, wait consumer to get it..
!--product still in list, wait consumer to get it..
:::consumer fetch: 91
!--no product now, wait producer put in...
:::producer put: 63
:::consumer fetch: 63
:::producer put: 85
!--product still in list, wait consumer to get it..
!--product still in list, wait consumer to get it..
:::consumer fetch: 85
!--no product now, wait producer put in...
:::producer put: 1
:::consumer fetch: 1
:::producer put: 26
!--product still in list, wait consumer to get it..
!--product still in list, wait consumer to get it..
:::consumer fetch: 26
!--no product now, wait producer put in...
:::producer put: 8
:::consumer fetch: 8
:::producer put: 19
!--product still in list, wait consumer to get it..
!--product still in list, wait consumer to get it..
:::consumer fetch: 19
!--no product now, wait producer put in...
:::producer put: 74
!--product still in list, wait consumer to get it..
:::consumer fetch: 74
:::producer put: 50
!--product still in list, wait consumer to get it..
:::consumer fetch: 50
!--no product now, wait producer put in...
:::producer put: 97
:::consumer fetch: 97
:::producer put: 69
!--product still in list, wait consumer to get it..
!--product still in list, wait consumer to get it..
:::consumer fetch: 69
!--no product now, wait producer put in...
:::producer put: 41
!--product still in list, wait consumer to get it..
:::consumer fetch: 41
:::producer put: 6
!--product still in list, wait consumer to get it..
:::consumer fetch: 6
!--no product now, wait producer put in...

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