下面来看看三种方法是如何来下载zip文件的：
方法一：
import urllib print "downloading with urllib"
url = 'http://www.jb51.net//test/demo.zip'
urllib.urlretrieve(url, "demo.zip")
方法二：
import urllib2
print "downloading with urllib2"
url = 'http://www.jb51.net//test/demo.zip'
f = urllib2.urlopen(url)
data = f.read()
with open("demo2.zip", "wb") as code:
code.write(data)
方法三：
import requests
print "downloading with requests"
url = 'http://www.jb51.net/test/demo.zip'
r = requests.get(url)
with open("demo3.zip", "wb") as code:
code.write(r.content)
看起来使用urllib最为简单，一句语句即可。当然你可以把urllib2缩写成：
f = urllib2.urlopen(url)
with open("demo2.zip", "wb") as code:
code.write(f.read())