urllib和urllib2区别 python2.x

【总述】可以把urllib2当作urllib的扩增，比较明显的优势是urllib2.urlopen可以接受Request对象作为参数，从而可以控制HTTP Request的header部。

作为一个Python菜鸟，之前一直懵懂于urllib和urllib2，以为2是1的升级版。今天看到老外写的一篇《Python:
difference between urllib and urllib2》才明白其中的区别。

 
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You
might be intrigued by the existence of two separate URL modules in Python -

urllib

 and 

urllib2

.
Even more intriguing: they are not alternatives for each other. So what is the difference between 

urllib

 and 

urllib2

,
and do we need them both? 
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你可能对于Python中两个独立存在的-urllib2和-urllib2感到好奇。更有趣的是：它们并不是可以相互代替的。那么这两个模块间的区别是什么，并且这两个我们都需要吗？

urllib

 and 

 urllib2are
both Python modules that do URL request related stuff but offer different functionalities. Their two most significant differences are listed below: 

urllib 和urllib2都是接受URL请求的相关模块，但是提供了不同的功能。两个最显著的不同如下：

urllib2

 can
accept a 

Request

 object
to set the headers for a URL request,

urllib

 accepts only
a URL. That means, you cannot masquerade your User Agent string etc.

urllib2可以接受一个Request类的实例来设置URL请求的headers，urllib仅可以接受URL。这意味着，你不可以伪装你的User Agent字符串等。
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urllib

 provides
the 

urlencode

 method
which is used for the generation of GET query strings, 

urllib2

 doesn't
have such a function. This is one of the reasons why 

urllib

 is
often used along with 

urllib2

.

urllib提供urlencode方法用来GET查询字符串的产生，而urllib2没有。这是为何urllib常和urllib2一起使用的原因。

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For other differences between 

urllib

 and 

urllib2

 refer
to their documentations, the links are given in the References section. 

Tip: if you are planning to do HTTP stuff only, check out httplib2,
it is much better than httplib or urllib or urllib2. 
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提示：如果你仅做HTTP相关的，看一下httplib2，比其他几个模块好用。
 
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相关资料
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这里还有个类似的问答：urllib
urllib2 what is the difference ?
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stackoverflow上也有：Should
I use urllib or urllib2?
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Python
Docs

urllib
urllib2

转自：http://www.cnblogs.com/yuxc/archive/2011/08/01/2124073.html

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