python入门学习day02

1. 模拟浏览器登录
   方法一：使用build_opener

import urllib.request
url="http://www.baidu.com"
headers=("user-agent")
opener= urllib.request.build_opener()
opener.addheaders=[headers]
data = opener.open(url).read()

方法二：使用add_header

import urllib.request
url= "http://www.baidu.com"
req=urllib.request.Request(url)
req.add_header('user-agent')
data=urllib.request.urlopen(req).read()

2. 登录超时设置

import urllib.request
for i in range(1,100):
   try:
       file = urllib.request.urlopen("http://www.baidu.com",timeout=30)
       date = file.read()
       print(len(data))
   except Exception as e:
       print("出现异常-->"+str(e))