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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