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python 百度百科的爬虫实例

2018-01-26 13:49 471 查看
本实例用的python版本为3.6。

爬虫启动类 spider_mainpy

url管理器 url_managerpy

html下载器 html_downerpy

html解析器 html_parserpy

html输出器 html_outputerpy

爬虫启动类 spider_main.py

from baike_spider import url_manager, html_downer, html_parser, html_outputer

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

def craw(self, begin_url):
count = 1
self.urls.add_new_url(begin_url)
while self.urls.has_new_url():
try:
if count > 100:
break
new_url = self.urls.get_new_url()
print("craw %d : %s" % (count, new_url))
html_content = self.downloader.download(new_url)
new_urls, new_data = self.parser.parse(new_url, html_content)
self.urls.add_new_urls(new_urls)
self.outputer.collect_data(new_data)
count += 1
except BaseException as e:
print(e)
print("craw fail")

self.outputer.output_html()

if __name__ == "__main__":
root_url = "https://baike.baidu.com/item/Python/407313"
obj_spider = SpiderMain()
obj_spider.craw(root_url)


url管理器 url_manager.py

class UrlManager(object):
def __init__(self):
self.new_urls = set()
self.old_urls = set()

def add_new_url(self, begin_url):
if begin_url is None:
return
if begin_url in self.new_urls or begin_url in self.old_urls:
return
self.new_urls.add(begin_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

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


html下载器 html_downer.py

import ssl
from urllib import request

class HtmlDownloader(object):

def download(self, new_url):
ssl._create_default_https_context = ssl._create_unverified_context
response = request.urlopen(new_url)
print("请求返回码：%d" % response.getcode())
if response.getcode() != 200:
return None
return response.read()


html解析器 html_parser.py

import re
from bs4 import BeautifulSoup
from urllib import parse

class HtmlParser(object):

def parse(self, new_url, html_content):
if html_content is None or new_url is None:
return
soup = BeautifulSoup(html_content, 'html.parser')
new_urls = self._get_new_urls(new_url, soup)
new_data = self._get_new_data(new_url, soup)
return new_urls,new_data

def _get_new_urls(self, new_url, soup):
full_urls = set()
links = soup.find_all("a", href=re.compile(r"/item/"))
for link in links:
url_href = link["href"]
full_url_href = parse.urljoin(new_url, url_href)
full_urls.add(full_url_href)
return full_urls

def _get_new_data(self, new_url, soup):
res_data = {"url": new_url}
# 获取title class="lemmaWgt-lemmaTitle-title"
title = soup.find("dd", class_="lemmaWgt-lemmaTitle-title").find("h1").get_text()
res_data["title"] = title
# 获取摘要  class = "lemma-summary"
summary = soup.find("div", class_="lemma-summary").get_text()
res_data["summary"] = summary
return res_data


html输出器 html_outputer.py

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

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

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

fout.write("<html>")
fout.write("<head>")
fout.write("<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\">")
fout.write("</head>")
fout.write("<body>")
fout.write("<table border = 1>")
for data in self.datas:
fout.write("<tr>")
fout.write("<td>%s<td>" % data['url'])
fout.write("<td>%s<td>" % data['title'])
fout.write("<td>%s<td>" % data['summary'])
fout.write("</tr>")
fout.write("</table>")
fout.write("</body>")
fout.write("</html>")
fout.close()
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