python爬虫常用模块

#!/usr/bin/env python
# coding: utf-8
__author__ = 'www.py3study.com'
import urllib.request
import time
import platform
import os
def clear():
    '''该函数用于清屏'''
    print(u'内容较多，显示3秒后翻页')
    time.sleep(3)
    OS = platform.system()
    if (OS == u'Windows'):
        os.system('cls')
    else:
        os.system('clear')

def linkbaidu():
    url = 'https://www.baidu.com'
    try:
        response = urllib.request.urlopen(url, timeout=3)
    except urllib.request.URLError:
        print(u'网络地址错误')
        exit()
    with open('baidu.txt','w') as fp:
        fp.write(response.read().decode('utf-8'))
    print(u'获取url信息，response,geturl() \n: {}'.format(response.geturl()))
    print(u'获取返回代码,response.getcode() \n:{}'.format(response.getcode()))
    print(u'获取返回信息，response.info() \n:{}'.format(response.info()))
    print(u'获取的网页内容以存放当前目录baidu.txt中，请自行查看')

if __name__ == '__main__':
    linkbaidu()