python 多线程应用介绍
python可以方便地支持多线程。可以快速创建线程、互斥锁、信号量等等元素,支持线程读写同步互斥。美中不足的是,python的运行在python 虚拟机上,创建的多线程可能是虚拟的线程,需要由python虚拟机来轮询调度,这大大降低了python多线程的可用性。我们经今天用了经典的生产者和消费者的问题来说明下python的多线程的运用 上代码:
#encoding=utf-8 import threading import random import time from Queue import Queue class Producer(threading.Thread): def __init__(self, threadname, queue): threading.Thread.__init__(self, name = threadname) self.sharedata = queue def run(self): for i in range(20): print self.getName(),'adding',i,'to queue' self.sharedata.put(i) time.sleep(random.randrange(10)/10.0) print self.getName(),'Finished' # Consumer thread class Consumer(threading.Thread): def __init__(self, threadname, queue): threading.Thread.__init__(self, name = threadname) self.sharedata = queue def run(self): for i in range(20): print self.getName(),'got a value:',self.sharedata.get() time.sleep(random.randrange(10)/10.0) print self.getName(),'Finished' # Main thread def main(): queue = Queue() producer = Producer('Producer', queue) consumer = Consumer('Consumer', queue) print 'Starting threads ...' producer.start() consumer.start() producer.join() consumer.join() print 'All threads have terminated.' if __name__ == '__main__': main()
你亲自运行下这断代码,可能有不一样的感觉!理解以后可以用python cookielib 再结果python urllib 写一个多线程下载网页的脚本应该没什么问题
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