python爬虫入门---第一篇：获取某一网页所有超链接

这是一个通过使用requests和BeautifulSoup库，简单爬取网站的所有超链接的小爬虫。有任何问题欢迎留言讨论。

import requests
from bs4 import BeautifulSoup

def getHTMLText(url):
    '''
    此函数用于获取网页的html文档
    '''
    try:
        #获取服务器的响应内容，并设置最大请求时间为6秒
        res = requests.get(url, timeout = 6)
        #判断返回状态码是否为200
        res.raise_for_status()
        #设置该html文档可能的编码
        res.encoding = res.apparent_encoding
        #返回网页HTML代码
        return res.text
    except:
        return '产生异常'

def main():
    '''
    主函数
    '''
    #目标网页，这个可以换成一个你喜欢的网站
    url = 'https://www.cnblogs.com/huwt/'

    demo = getHTMLText(url)

    #解析HTML代码
    soup = BeautifulSoup(demo, 'html.parser')

    #模糊搜索HTML代码的所有包含href属性的<a>标签
    a_labels = soup.find_all('a', attrs={'href': True})

    #获取所有<a>标签中的href对应的值，即超链接
    for a in a_labels:
        print(a.get('href'))

main()

测试结果：

https://www.cnblogs.com/huwt/
https://www.cnblogs.com/huwt/
https://www.cnblogs.com/
https://www.cnblogs.com/huwt/
https://i.cnblogs.com/EditPosts.aspx?opt=1
https://msg.cnblogs.com/send/%E8%B7%AF%E6%BC%AB%E6%BC%AB%E6%88%91%E4%B8%8D%E7%95%8F
https://www.cnblogs.com/huwt/rss
https://i.cnblogs.com/
https://www.cnblogs.com/huwt/archive/2019/04/10.html
https://www.cnblogs.com/huwt/p/10680209.html
https://www.cnblogs.com/huwt/p/10680209.html
https://i.cnblogs.com/EditPosts.aspx?postid=10680209
https://www.cnblogs.com/huwt/p/10685968.html
https://www.cnblogs.com/huwt/p/10685968.html
https://i.cnblogs.com/EditPosts.aspx?postid=10685968
https://www.cnblogs.com/huwt/archive/2019/04/08.html
https://www.cnblogs.com/huwt/p/10673470.html
https://www.cnblogs.com/huwt/p/10673470.html
https://i.cnblogs.com/EditPosts.aspx?postid=10673470
https://www.cnblogs.com/huwt/archive/2019/03/31.html
https://www.cnblogs.com/huwt/p/10633896.html
https://www.cnblogs.com/huwt/p/10633896.html
https://i.cnblogs.com/EditPosts.aspx?postid=10633896
https://www.cnblogs.com/huwt/p/10632084.html
https://www.cnblogs.com/huwt/p/10632084.html
https://i.cnblogs.com/EditPosts.aspx?postid=10632084
https://www.cnblogs.com/huwt/archive/2019/03/30.html
https://www.cnblogs.com/huwt/p/10629625.html
https://www.cnblogs.com/huwt/p/10629625.html
https://i.cnblogs.com/EditPosts.aspx?postid=10629625
https://www.cnblogs.com/huwt/archive/2019/03/25.html
https://www.cnblogs.com/huwt/p/10597502.html
https://www.cnblogs.com/huwt/p/10597502.html
https://i.cnblogs.com/EditPosts.aspx?postid=10597502
https://www.cnblogs.com/huwt/archive/2019/03/24.html
https://www.cnblogs.com/huwt/p/10591353.html
https://www.cnblogs.com/huwt/p/10591353.html
https://i.cnblogs.com/EditPosts.aspx?postid=10591353
https://www.cnblogs.com/huwt/archive/2019/03/16.html
https://www.cnblogs.com/huwt/p/10540942.html
https://www.cnblogs.com/huwt/p/10540942.html
https://i.cnblogs.com/EditPosts.aspx?postid=10540942
https://www.cnblogs.com/huwt/p/10541675.html
https://www.cnblogs.com/huwt/p/10541675.html
https://i.cnblogs.com/EditPosts.aspx?postid=10541675
https://www.cnblogs.com/huwt/default.html?page=2
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