第18章 多线程编程(5)

18.5.4 生产者-消费者问题和Queue模块

from random import randint
from time import sleep
from Queue import Queue
from MyThread import MyThread

def writeQ(queue):
    print 'producting object for Q...'
    queue.put('xxx', 1)
    print 'size now: ', queue.qsize()
    
def readQ(queue):
    val = queue.get(1)
    print 'consumed object from Q... size now: ', queue.qsize()
    
def writer(queue, loops):
    for i in range(loops):
        writeQ(queue)
        sleep(randint(1, 3))

def reader(queue, loops):
    for i in range(loops):
        readQ(queue)
        sleep(randint(2, 5))

funcs = [writer, reader]
nfuncs = range(len(funcs))

nloops = randint(2, 5)
q = Queue(32)

threads = []
for i in nfuncs:
    t = MyThread(funcs[i], (q, nloops), funcs[i].__name__)
    threads.append(t)

for i in nfuncs:
    threads[i].start()
    
for i in nfuncs:
    threads[i].join()

print 'ALL DONE...'
           

Queue模块可以用来进行线程间通讯，让各个线程之间共享数据。

由于Python解释器是单线程的，所以不是所有的程序都能从多线程中得到好处。