Python requests convert to urlib2

I can login and get the source page properly using requestspackage. Beacause of some reason I can only use the standard library. unfortunately the urlib2 didn't get the same result as request,did I missed some thing?

requests

def login(userName, passWord):
        url = "https://logindict.youdao.com/login/acc/login"
        payload = "username=" + userName + "&password=" + passWord + \
            "&savelogin=1&app=web&tp=urstoken&cf=7&fr=1&ru=http%3A%2F%2Fdict.youdao.com%2Fwordbook%2Fwordlist%3Fkeyfrom%3Dnull&product=DICT&type=1&um=true"
        headers = {
            'cache-control': "no-cache",
            'content-type': "application/x-www-form-urlencoded"
        }
        s = requests.session()
        response = s.post(url, data=payload, headers=headers)
        print response.text

urllib2

url = "https://logindict.youdao.com/login/acc/login"
data = 'app=web&tp=urstoken&cf=3&fr=1&ru=http%3A%2F%2Fdict.youdao.com%2Fwordbook%2Fwordlist%3Fkeyfrom%3Dlogin_from_dict2.index&product=DICT&type=1&um=true&username=xxx&password=xxx'
headers = {
    'cache-control': "no-cache",
    "Content-Type": "application/x-www-form-urlencoded"
}

req = urllib2.Request(url, data=value, headers=headers)
response = urllib2.urlopen(req)
the_page = response.read()
print the_page

Solution

Because you don't have cookie that webserver will write/check, while request will do automate.
Use urllib2 with cookielib like below:

import urllib2
import cookielib
def login(userName, passWord):
    url = "https://logindict.youdao.com/login/acc/login"
    payload = "username=" + userName + "&password=" + passWord + \
        "&savelogin=1&app=web&tp=urstoken&cf=7&fr=1&ru=http%3A%2F%2Fdict.youdao.com%2Fwordbook%2Fwordlist%3Fkeyfrom%3Dnull&product=DICT&type=1&um=true"
    headers = {
        'cache-control': "no-cache",
        'content-type': "application/x-www-form-urlencoded"
    }
    url = url + '?' + payload
    req = urllib2.Request(url, headers=headers)
    cookie = cookielib.CookieJar()
    opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cookie))
    urllib2.install_opener(opener)
    response = urllib2.urlopen(req)
    the_page = response.read()
    print the_page

login('xxxxxx','xxxxx')

BTW, you need change your passwd now!