from bs4 import BeautifulSoup 
import requests 
import csv 
import bs4 
 
 
#检查url地址 
def check_link(url): 
 try: 
   
  r = requests.get(url) 
  r.raise_for_status() 
  r.encoding = r.apparent_encoding 
  return r.text 
 except: 
  print('无法链接服务器！！！') 
 
 
#爬取资源 
def get_contents(ulist,rurl): 
 soup = BeautifulSoup(rurl,'lxml') 
 trs = soup.find_all('tr') 
 for tr in trs: 
  ui = [] 
  for td in tr: 
   ui.append(td.string) 
  ulist.append(ui) 
  
#保存资源 
def save_contents(urlist): 
 with open("D:/2016年中国企业500强排行榜.csv",'w') as f: 
  writer = csv.writer(f) 
  writer.writerow(['2016年中国企业500强排行榜']) 
  for i in range(len(urlist)): 
   writer.writerow([urlist[i][1],urlist[i][3],urlist[i][5]]) 
def main(): 
 urli = [] 
 url = "http://www.maigoo.com/news/463071.html" 
 rs = check_link(url) 
 get_contents(urli,rs) 
 save_contents(urli) 
 
main()