爬虫(小案例）

点开其中一个链接， http://desk.zol.com.cn/dongman/huoyingrenzhe/（前面为浏览器自动补全，在代码里需要自己补全）

可以看到图片的下载地址以及打开本图集下一张图片的链接

了解完网站的图片构造后动手写代码，我们筛选出图集的链接后，通过图集的链接找到第一张图片下载地址和第二张图片的链接，通过第二张的链接找到第二张的下载地址和第三张的链接，循环下去，直到本图集到底，接着开始第二个图集，直到所有图集下载完毕，代码如下，为了方便循环，我们集成下载图片功能为download函数，解析图片网址功能为parses_picture：

from bs4 import BeautifulSoup
import requestsdef download(img_url, headers, n):req = requests.get(img_url, headers=headers)name = '%s' % n + '=' + img_url[-15:]path = r'C:\Users\asus\Desktop\火影壁纸1'file_name = path + '\\' + namef = open(file_name, 'wb')f.write(req.content)f.closedef parses_picture(url, headers, n):url = r'http://desk.zol.com.cn/' + urlimg_req = requests.get(url, headers=headers)img_req.encoding = 'gb2312'html = img_req.textbf = BeautifulSoup(html, 'lxml')try:img_url = bf.find('div', class_='photo').find('img').get('src')download(img_url, headers, n)url1 = bf.find('div', id='photo-next').a.get('href')parses_picture(url1, headers, n)except:print(u'第%s图片集到头了' % n)if __name__ == '__main__':url = 'http://desk.zol.com.cn/dongman/huoyingrenzhe/'headers = {"User-Agent": "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36"}req = requests.get(url=url, headers=headers)req = requests.get(url=url, headers=headers)req.encoding = 'gb2312'html = req.textbf = BeautifulSoup(html, 'lxml')targets_url = bf.find_all('li', class_='photo-list-padding')n = 1for each in targets_url:url = each.a.get('href')parses_picture(url, headers, n)n = n + 1

 如果要抓取百度上面搜索关键词为Jecvay Notes的网页, 则代码如下

import urllib
import urllib.requestdata={}
data['word']='Jecvay Notes'url_values=urllib.parse.urlencode(data)
url="http://www.baidu.com/s?"
full_url=url+url_valuesdata=urllib.request.urlopen(full_url).read()
data=data.decode('UTF-8')
print(data)