使用 multiprocessing.dummy 执行多线程任务

# -*- coding: utf-8 -*-
# from multiprocessing import Pool 多进程
from multiprocessing.dummy import Pool as ThreadPool
import time
import urllib2

urls = [
    'http://www.python.org',
    'http://www.python.org/about/',
    'http://www.onlamp.com/pub/a/python/2003/04/17/metaclasses.html',
    'http://www.python.org/doc/',
    'http://www.python.org/download/',
    'http://www.python.org/getit/',
    'http://www.python.org/community/',
    'https://wiki.python.org/moin/',
    'http://planet.python.org/',
    'https://wiki.python.org/moin/LocalUserGroups',
    'http://www.python.org/psf/',
    'http://docs.python.org/devguide/',
    'http://www.python.org/community/awards/'
    ]

# 单线程
start = time.time()
results = map(urllib2.urlopen, urls)
print 'Normal:', time.time() - start

# 多线程
start2 = time.time()
# 开4个 worker，没有参数时默认是 cpu 的核心数
pool = ThreadPool(4)
# 在线程中执行 urllib2.urlopen(url) 并返回执行结果
results2 = pool.map(urllib2.urlopen, urls)
pool.close()
pool.join()
print 'Thread Pool:', time.time() - start2