找到一段可行的python的多线程例子~

CODE:

import os
import time
import threading

# 进程函数
def printthread(n):
   
    print n,"-->进程创建"
    for a in range(4):
        print a
        time.sleep(1)
    print n,"-->进程结束"
    sem.release()
   

if __name__ =='__main__':

    maxThread=5
    #
    sem=threading.BoundedSemaphore(maxThread)
   
    for a in range(12):
   
        sem.acquire()
        threading.Thread(target=printthread,args=(a,)).start()

    print "All thread has create,Wait for all thread exit."
   
    for a in range(maxThread):
        sem.acquire();
   
    print "All thread exit"