python urllib2三种爬虫方式

#__author__ = 'DouYunQian'

 #coding=utf-8

 import urllib2

 url="https://www.baidu.com/s"

 print u"第一种方法",type(u"第一种方法"),type("第一种方法")

 response=urllib2.urlopen(url)

 print response.getcode()

 print len(response.read())

 print "第二种方法"

 request=urllib2.Request(url)

 request.add_header("User-Agent","Mozilla/5.0")

 request.add_data("{wd:'welcome'}")

 response=urllib2.urlopen(request)

 print response.code

 print len(response.read())





 print "第三种方法"

 import cookielib

 ck=cookielib.CookieJar()

 opener=urllib2.build_opener(urllib2.HTTPCookieProcessor(ck))

 urllib2.install_opener(opener)

 response=urllib2.urlopen(url)

 print response.getcode()



 print len(response.read())