Python实现多线程的两种方式分析

本文实例讲述了Python实现多线程的两种方式。分享给大家供大家参考，具体如下：

目前python 提供了几种多线程实现方式 thread，threading，multithreading ,其中thread模块比较底层，而threading模块是对thread做了一些包装，可以更加方便的被使用。

2.7版本之前python对线程的支持还不够完善，不能利用多核CPU，但是2.7版本的python中已经考虑改进这点，出现了multithreading  模块。threading模块里面主要是对一些线程的操作对象化，创建Thread的class。一般来说，使用线程有两种模式:

• A 创建线程要执行的函数，把这个函数传递进Thread对象里，让它来执行；
• B 继承Thread类，创建一个新的class，将要执行的代码 写到run函数里面。

本文介绍两种实现方法。

第一种 创建函数并且传入Thread 对象中

t.py 脚本内容

import threading,time
from time import sleep, ctime
def now() :
 return str( time.strftime( '%Y-%m-%d %H:%M:%S' , time.localtime() ) )
def test(nloop, nsec):
 print 'start loop', nloop, 'at:', now()
 sleep(nsec)
 print 'loop', nloop, 'done at:', now()
def main():
 print 'starting at:',now()
 threadpool=[]
 for i in xrange(10):
  th = threading.Thread(target= test,args= (i,2))
  threadpool.append(th)
 for th in threadpool:
  th.start()
 for th in threadpool :
  threading.Thread.join( th )
 print 'all Done at:', now()
if __name__ == '__main__':
  main()

执行结果：

starting at: 2018-08-29 09:34:16
start loop 0 at: 2018-08-29 09:34:16
start loop 1 at: 2018-08-29 09:34:16
start loop 2 at: 2018-08-29 09:34:16start loop 3 at: 2018-08-29 09:34:16

start loop 4 start loopat:  52018-08-29 09:34:16
at: 2018-08-29 09:34:16
start loop 6 at: start loop2018-08-29 09:34:16
7 at: 2018-08-29 09:34:16
start loop 8 start loopat: 9  2018-08-29 09:34:16at:
 2018-08-29 09:34:16
looploop 1 done at: 2018-08-29 09:34:18
 0 done at: 2018-08-29 09:34:18
loop 3 done at: 2018-08-29 09:34:18
looploop 5 done at: 2018-08-29 09:34:18
 2 done at: 2018-08-29 09:34:18
loop 4 done at: 2018-08-29 09:34:18
looploop 7 done at: 2018-08-29 09:34:18
 6 done at: 2018-08-29 09:34:18
looploop  98  done at:done at:  2018-08-29 09:34:182018-08-29 09:34:18

all Done at: 2018-08-29 09:34:18

第二种 创建继承自Thread的类

thclass.py 脚本内容：

import threading , time
from time import sleep, ctime
def now() :
 return str(time.strftime('%Y-%m-%d %H:%M:%S' , time.localtime()))
class myThread (threading.Thread) :
 """docstring for myThread"""
 def __init__(self, nloop, nsec) :
  super(myThread, self).__init__()
  self.nloop = nloop
  self.nsec = nsec
 def run(self):
  print 'start loop', self.nloop, 'at:', ctime()
  sleep(self.nsec)
  print 'loop', self.nloop, 'done at:', ctime()
def main():
 thpool = []
 print 'starting at:', now()
 for i in xrange(10):
  thpool.append(myThread(i, 2))
 for th in thpool:
  th.start()
 for th in thpool:
  th.join()
 print 'all Done at:', now()
if __name__ == '__main__':
  main()

执行结果：

starting at: 2018-08-29 09:36:02
start loop 0 at: Wed Aug 29 09:36:02 2018
start loop 1 at: Wed Aug 29 09:36:02 2018
start loop 2 at: Wed Aug 29 09:36:02 2018
start loop 3 at: Wed Aug 29 09:36:02 2018
start loop 4 at: Wed Aug 29 09:36:02 2018
 start loop 5 at: Wed Aug 29 09:36:02 2018
start loop 6 at: Wed Aug 29 09:36:02 2018
start loop 7 at: Wed Aug 29 09:36:02 2018
start loop 8 at: Wed Aug 29 09:36:02 2018
start loop 9 at: Wed Aug 29 09:36:02 2018
loop 0 done at: Wed Aug 29 09:36:04 2018
loop 1 done at: Wed Aug 29 09:36:04 2018
looploop  23  done at:done at:  Wed Aug 29 09:36:04 2018Wed Aug 29 09:36:04 2018

loop 4 done at: Wed Aug 29 09:36:04 2018
loop 5 done at: Wed Aug 29 09:36:04 2018
loop 6 done at: Wed Aug 29 09:36:04 2018
looploop loop 8 9 7 done at: done at: done at: Wed Aug 29 09:36:04 2018 Wed Aug 29 09:36:04 2018
Wed Aug 29 09:36:04 2018

all Done at: 2018-08-29 09:36:04

希望本文所述对大家Python程序设计有所帮助。