python 多线程 和 多进程
单线程例子：#!/usr/bin/python
# -*- coding:UTF-8 -*-
# Name: danxiancheng.py
import time
import threading
def loop(num,sec):
print 'loop %s start: ....' % num, time.strftime('%Y-%M-%d %H:%m:%S')
time.sleep(sec)
print 'loop %s stop: .....' % num, time.strftime('%Y-%M-%d %H:%m:%S')
def main():
print '\nStarting: ........', time.strftime('%Y-%M-%d %H:%m:%S'), '\n'
mysec =
for i in range(len(mysec)):
loop(i,mysec)
print '\nAll DONE: ........', time.strftime('%Y-%M-%d %H:%m:%S'), '\n'
if __name__=='__main__':
main()
打印结果：
# python singlethread.py
Starting: ........ 2012-33-27 05:12:12
loop 0 start: .... 2012-33-27 05:12:12
loop 0 stop: ..... 2012-33-27 05:12:15
loop 1 start: .... 2012-33-27 05:12:15
loop 1 stop: ..... 2012-33-27 05:12:20
loop 2 start: .... 2012-33-27 05:12:20
loop 2 stop: ..... 2012-33-27 05:12:26
loop 3 start: .... 2012-33-27 05:12:26
loop 3 stop: ..... 2012-33-27 05:12:34
All DONE: ........ 2012-33-27 05:12:34
#
多线程的例子：
#!/usr/bin/python
# -*- coding:UTF-8 -*-
# Name: duoxiancheng.py
import time
import threading
def loop(num,sec):
print 'loop %s start: ....' % num, time.strftime('%Y-%M-%d %H:%m:%S')
time.sleep(sec)
print 'loop %s stop: .....' % num, time.strftime('%Y-%M-%d %H:%m:%S')
def main():
print '\nStarting: ........', time.strftime('%Y-%M-%d %H:%m:%S'), '\n'
mysec =
mythreads = )) for i in range(len(mysec))]
for i in mythreads:
i.start()
for i in mythreads:
i.join()
print '\nAll DONE: ........', time.strftime('%Y-%M-%d %H:%m:%S'), '\n'
if __name__=='__main__':
main()
执行结果：
# python mutithread.py
Starting: ........ 2012-36-27 05:12:19
loop 0 start: .... 2012-36-27 05:12:19
loop 1 start: .... 2012-36-27 05:12:19
loop 2 start: .... 2012-36-27 05:12:19
loop 3 start: .... 2012-36-27 05:12:19
loop 0 stop: ..... 2012-36-27 05:12:22
loop 1 stop: ..... 2012-36-27 05:12:24
loop 2 stop: ..... 2012-36-27 05:12:25
loop 3 stop: ..... 2012-36-27 05:12:27
All DONE: ........ 2012-36-27 05:12:27
结论：
可以看到单线程中的两个循环， 只有一个循环结束后另一个才开始。而多线程则是进程内所有线程一起执行，同步任务。
首先创建了n个线程，并将其存放到mythreads列表中，这里用到的是给Thread类传递了函数，第一个for循环是让两个线程开始执行。第二个for循环再让每个线程分别调用join函数，使程序挂起，直至相应线程都执行结束。
多进程例子：
test.py
#!/usr/bin/python
import time
import os
from os import environ
class MyClass:
def __init__(self):
self.aa = 1
def getA(self):
return environ['FOO']
def subA(self):
self.aa += 1
if __name__ == '__main__':
pass
pro.py
#!/usr/bin/python
import os
import sys
import time, datetime, traceback
from os import environ
from multiprocessing import Process
from test import MyClass
def create_compute(hostname):
try:
environ['FOO'] = hostname
a = MyClass()
print a.getA()
except Exception as e:
print e
traceback.print_exc()
if __name__ == '__main__':
plist = []
for i in 4,5:
p = Process(target = create_compute, args = ('node'+str(i),))
plist.append(p);
p.start()
for p in plist:
p.join()
执行结果：
# python pro.py
node4
node5
#
结论：
两个进程中设置的环境变量 互不影响
多进程：
http://blog.csdn.net/inte_sleeper/article/details/6741963
多线程：
http://blog.chinaunix.net/uid-16362696-id-2746820.html
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