python下载文件的三种方法

Python开发中时长遇到要下载文件的情况，最常用的方法就是通过Http利用urllib或者urllib2模块，此外Python还提供了另外一种方法requests。

下面来看看三种方法是如何来下载文件的：

方法一：

import urllib

print "downloading with urllib"
url = 'http://download.redis.io/releases/redis-5.0.5.tar.gz'
print "downloading with urllib"
urllib.urlretrieve(url, "demo.zip")

方法二：

import urllib2

print "downloading with urllib2"
url = 'http://download.redis.io/releases/redis-5.0.5.tar.gz'

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://download.redis.io/releases/redis-5.0.5.tar.gz' 
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：

import urllib2

f = urllib2.urlopen(url)
  with open("http://download.redis.io/releases/redis-5.0.5.tar.gz", "wb") as code:
    code.write(f.read())