python简单爬虫爬取百度百科python词条网页

目标分析：
目标：百度百科python词条相关词条网页 - 标题和简介

入口页：https://baike.baidu.com/item/Python/407313

URL格式：
- 词条页面URL：/item/xxxx

数据格式：
- 标题：
<dd class="lemmaWgt-lemmaTitle-title"><h1>***</h1></dd>

- 简介：
<div class="lemma-summary">***</div>

页面编码：utf-8

爬虫主入口文件

spider_main.py

# coding:utf-8

import url_manager

import html_downloader

import html_parser

import html_outputer

class SpiderMain(object):

    def __init__(self):

        # url管理器

        self.urls = url_manager.UrlManager()

        # 下载器

        self.downloader = html_downloader.HtmlDownloader()

        # 解析器

        self.parser = html_parser.HtmlParser()

        # 输出控制器

        self.outputer = html_outputer.HtmlOutputer()

    def craw(self, root_url):

        # 记录当前爬取的是第几个url

        count = 1

        self.urls.add_new_url(root_url)

        # 如果有待爬取的url就继续while循环

        '''

        while self.urls.has_new_url():

            try:

                new_url = self.urls.get_new_url()

                print 'craw %d : %s' % (count, new_url)

                # 下载url页面

                html_cont = self.downloader.download(new_url)

                # 进行url解析并获取url的数据

                new_urls, new_data = self.parser.parse(new_url, html_cont)

                # url解析及数据搜集

                self.urls.add_new_urls(new_urls)

                self.outputer.collect_data(new_data)

                if count >= 1000:

                    break

                count = count + 1

            except Exception as e:

                print 'craw failed'

                print e

        '''

        while self.urls.has_new_url():

            new_url = self.urls.get_new_url()

            print 'craw %d : %s' % (count, new_url)

            # 下载url页面

            html_cont = self.downloader.download(new_url)

            # print html_cont

            # 进行url解析并获取url的数据

            new_urls, new_data = self.parser.parse(new_url, html_cont)

            # url解析及数据搜集

            self.urls.add_new_urls(new_urls)

            self.outputer.collect_data(new_data)

            if count >= 10:

                break

            count = count + 1

        # 输出到指定页面

        self.outputer.output_html()

if __name__ == "__main__":

    root_url = "https://baike.baidu.com/item/Python/407313"

    obj_spider = SpiderMain()

    obj_spider.craw(root_url)

网页管理器

url_manager.py

# coding:utf-8

class UrlManager(object):

    def __init__(self):

        # 要爬取的url

        self.new_urls = set()

        # 爬取过的url

        self.old_urls = set()

    def add_new_url(self, url):

        if url is None:

            return

        # 如果url不在要爬取的url里面也不在爬取过的url里面就添加进来

        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

网页下载器

html_downloader.py

# coding:utf-8

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()

网页分析器

html_parser.py

# coding:utf-8

from bs4 import BeautifulSoup

import re

import urlparse

class HtmlParser(object):

    def _get_new_urls(self, page_url, soup):

        # 得到所有的词条url

        links = soup.find_all('a', href=re.compile(r"/item/.*"))

        # print links

        new_urls = set()

        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 = {}

        # url

        res_data['url'] = page_url

        # <dd class="lemmaWgt-lemmaTitle-title">

        # <h1>Python</h1>

        title_node = soup.find('dd', class_='lemmaWgt-lemmaTitle-title').find("h1")

        res_data['title'] = title_node.get_text()

        # <div class="lemma-summary" label-module="lemmaSummary">

        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', 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

网页输出器

html_outputer.py

# coding:utf-8

class HtmlOutputer(object):

    def __init__(self):

        self.datas = []

    def collect_data(self, data):

        if data is None:

            return

        self.datas.append(data)

    # ascii

    def output_html(self):

        fout = open('output.html', 'w')

        fout.write("<html>")

        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")

运行代码：

结果页面

python简单爬虫爬取百度百科python词条网页的相关教程结束。