python提供多线程编程模块有三个：thread、threading、Queen，主要使用threading模块
主要原因是因为：首先threading模块比thread模块更先进，对线程支持更为完善。其次，thread模块同步语言很少，而threading模块则很多。
1、thread模块
start_new_thread()函数是thread 模块的一个关键函数，它的语法与内建的apply()函数完全
一样，其参数为：函数，函数的参数以及可选的关键字参数。不同的是，函数不是在主线程里运行，而是产生一个新的线程来运行这个函数。
start_new_thread()要求一定要有前两个参数。所以，就算我们想要运行的函数不要参数，我们也要传一个空的元组。
<pre>import thread
from time import ctime,sleep
loops[4,2]
def loop(nloop,nsec,lock):
print 'start loop', nloop 'at',ctime()
sleep(nsec)
print 'loop',nloop 'done at',ctime()
lock.release() #释放线程锁
def mian():
print 'starting at',ctime()
nloops=range(len(loops))
locks=[]
for i in nloops:
lock=thread.allocate_lock() #产生一个线程锁
lock.acquire() #获得线程锁的实例
locks.append(lock)
for i in nloops:
thread.start_new_thread(loop,(i,loops[i],locks[i]) #开启线程
for i in nloops :
while locks[i].locked():pass
if __name__== '__main__':
main()</pre>
2、threding模块
<pre>from time import ctime ,sleep
import thread,threading
loops=[4,2]
class Mythread(threading.Thread):
def __init__(self,func,args,name):
threading.Thread.__init__(self)
self.func=func
self.args=args
self.name=name
def run(self):
apply(self.func,self.args)
def loop(nloop,nsec):
print 'start loop',nloop,' at:',ctime()
sleep(nsec)
print 'loop',nloop,' done at',ctime()
def main():
print 'start at',ctime()
threads=[]
nloops=range(len(loops))
for i in nloops:
t=Mythread(loop,(i,loops[i]),loop.name)
threads.append(t)
for i in nloops:
threads[i].start()
for i in nloops:
threads[i].join()
print 'all done at',ctime()
if __name__ == '__main__':
main()</pre>
3、Queue模块可以实现线程同步先进先出
<pre>
from Queue import Queue
import threading
from time import sleep
from random import randint
def writeQ(queue):
print 'prducing 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 loops:
writeQ(queue)
sleep(4)
def reader(queue,loops):
for i in loops:
readQ(queue)
sleep(2)
funcs=[writer,reader]
nloops=range(len(funcs))
def main():
threads=[]
queue= Queue(32)
loops=range(randint(2,5))
for i in nloops:
t=threading.Thread(target=funcs[i],args=(queue,loops))
threads.append(t)
for i in nloops:
threads[i].start()
for i in nloops:
threads[i].join()
print 'all done'
if __name__ == '__main__':
main()
