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.

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.