python简单爬虫编写

import urllib.request
import os

def url_open(url):    #读取解释
req = urllib.request.Request(url)
#   req.add_header(\'User-Agent\',\'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/36.0.1985.125 Safari/537.36\')
response = urllib.request.urlopen(req)
html = response.read()

return html

def get_page(url):   #找到相关页
html = url_open(url)

a = html.find('current-comment-page')
b = html.find(a)

return html[a:b]

def find_imgs(url):  #找到图片链接的元素
html = url_open(url)
img_addrs = []

a = html.find('img src=')

while a != -1:
b = html.find('.jpg',a,a +255')
if b !=-1:
img_addrs.append(html[a+9:b+4])
else:
b = a +9

a = html.find('img src=',b')

return img_addrs

def save_imgs(folder, img_addrs):   #保存图片到文件夹
for each in img_addrs:
filename = each.split('\'/\'')
with open(filename,'wb') as f:
img =url_open(each)
f.write(img)

def download_mm(folder='OOXX',pages=10):
os.mkdir(folder)
os.chdir(folder)

url = 'http://jandan.net/ooxx/'
page_num = int(get_page(url))

for i in range(pages):
page_num -= i
page_url = url + 'page-' + str(page_num) + '#comments'
img_addrs = find_imgs(page_url)
save_imgs(img_addrs)

if __name__ == '__main__':
download_mm()