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：
import threading
import random
import time
from Queue import Queueclass 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
