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Python 爬虫的实践运用(1)--爬取百度百科的词条

2016-01-03 11:03 701 查看

参考地址:

Python开发简单爬虫

简介:

一共分为5个部分:

spider_main #主程序

UrlManager #url管理

HtmlDownloader #网页下载器

HtmlParser #网页解析器

HtmlOutputer #解析结果输出

具体代码:

spider_main

#coding utf8

from BaiduBaike import html_download, html_parser, html_outputer, url_Manager

class SpiderMain(object):
def __init__(self):
self.urls = url_Manager.UrlManager()
self.downloader = html_download.HtmlDownloader()
self.parser = html_parser.HtmlParser()
self.outputer = html_outputer.HtmlOutputer()

def craw(self, root_url):
count = 1
self.urls.add_new_url(root_url)
while self.urls.has_new_url():
try:
new_url = self.urls.get_new_url()
print 'craw %d : %s'% (count,new_url)
html_cont = self.downloader.download(new_url)
new_urls ,new_data = self.parser.parse(new_url,html_cont)
self.urls.add_new_urls(new_urls)
self.outputer.collect_data(new_data)

if count == 100:
break

count = count + 1
except:
print 'craw failed'

self.outputer.output_html()

if __name__ == '__main__':
root_url = 'http://baike.baidu.com/view/21087\.htm'
obj_spider = SpiderMain()
obj_spider.craw(root_url)

UrlManager

#coding utf8

class UrlManager(object):

def __init__(self):
self.new_urls = set()
self.old_urls = set()

def add_new_url(self,url):
if url is None:
return
if url not in self.new_urls and url not in self.old_urls:
self.new_urls.add(url)

def add_new_urls(self,urls):
if urls is None or len(urls) == 0:
return
for url in urls:
self.add_new_url(url)

def has_new_url(self):
return len(self.new_urls) != 0

def get_new_url(self):
new_url = self.new_urls.pop()
self.old_urls.add(new_url)
return new_url

HtmlDownloader:

#coding utf8

import urllib2

class HtmlDownloader(object):
def download(self, url):
if url is None:
return None

response = urllib2.urlopen(url)

if response.getcode() != 200:
return None

return response.read()

HtmlParser:

#coding utf8
from bs4 import BeautifulSoup
import re
import urlparse
from test.inspect_fodder import Tit

class HtmlParser(object):

def _get_new_urls(self, page_url, soup):
new_urls = set()
#21087
links = soup.find_all('a', href=re.compile(r'/view/\d+\.htm'))
for link in links:
new_url = link['href']
new_full_url = urlparse.urljoin(page_url, new_url)
new_urls.add(new_full_url)
return new_urls

def _get_new_data(self, page_url, soup):
res_data = {}

res_data['url'] = page_url

title_node = soup.find('dd', class_='lemmaWgt-lemmaTitle-title').find('h1')
res_data['title'] = title_node.get_text()

summary_node = soup.find('div', class_='lemma-summary')
res_data['summary'] =  summary_node.get_text()

return res_data

def parse(self, page_url, html_cont):
if page_url is None or html_cont is None:
return

soup = BeautifulSoup(html_cont, 'html.parser',
4000
from_encoding='utf-8')
new_urls = self._get_new_urls(page_url,soup)
new_data = self._get_new_data(page_url,soup)
return new_urls, new_data

HtmlOutputer :

#coding utf8

class HtmlOutputer(object):
def __init__(self):
self.datas = []

def collect_data(self, data):
if data is None:
return
self.datas.append(data)

def output_html(self):
fout = open('output.html','w')

fout.write('<html>')
fout.write('<meta charset="utf-8">')
fout.write('<body>')
fout.write('<table>')
for data in self.datas:
fout.write('<tr>')
fout.write('<td>%s</td>' % data['url'])
fout.write('<td>%s</td>' % data['title'].encode('utf-8'))
fout.write('<td>%s</td>' % data['summary'].encode('utf-8'))
fout.write('</tr>')

fout.write('</table>')
fout.write('</body>')
fout.write('</html>')

结果展示:

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标签： python 爬虫

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