python实现下载文件的三种方法_python

import urllib 
import urllib2 
import requests
print "downloading with urllib" 
url = 'http://www.jb51.net//test/demo.zip' 
print "downloading with urllib"
urllib.urlretrieve(url, "demo.zip")

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)

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)

f = urllib2.urlopen(url) 
with open("demo2.zip", "wb") as code:
  code.write(f.read())