操作的url:  http://tieba.baidu.com/p/2887364960?see_lz=1&pn=1

import urllib.request
import http.client
import bs4
import re
pattern=re.compile('post_content_[0-9]{1,}')
def IsRightId(id):
             group=pattern.findall(id)
             if group:
                          return group
             else :
                          return None
def GetEveryPage(url,file):
             try:
                          rep=urllib.request.urlopen(url)
             except http.client.HTTPException as e:
                          print(repr(e))
             else:
                          rep_utf=rep.read().decode('gbk').encode(encoding='utf-8').decode('utf-8')
                          
                          soup=bs4.BeautifulSoup(rep_utf)
                          for div in soup.find_all('div'):
                                       div_id=div.get('id')
                                       if IsRightId(str(div_id)):
                                                    file.write(div.get_text()+'\r\n')
                         
                          
url='http://tieba.baidu.com/p/2887364960?see_lz=1&pn='
file_tieba=open('007.txt','w+',encoding='utf-8')
for i in range(1,17):
             url_everypage=url+str(i)
             print('Processing page:'+str(i)+str('/16......'))
             GetEveryPage(url_everypage,file_tieba)
print('Finished!')
file_tieba.close()