如何使用python实现垂直爬虫系统

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html_downloader

from urllib import requestdef download(url):    if url is None:        return    response = request.urlopen(url)    if response.getcode() != 200:        return None    return response.read()

html_outeputer

data_list = []def collect_data(data):    data_list.append(data)def output_html():    fout = open('output.html', 'w')    fout.write('')    fout.write('')    fout.write('')    for dataitem in data_list:        fout.write('')        fout.write('' % dataitem['url'])        fout.write('' % dataitem['title'])        fout.write('' % dataitem['datetime'])        fout.write('' % dataitem['visitcount'])        fout.write('')    fout.write('
%s
%s
%s
%s
')    fout.write('')    fout.write('')    fout.close()

html_parser

import refrom bs4 import BeautifulSoupfrom urllib.parse import urljoindef get_new_urls(page_url, soup):    new_urls = set()    links = soup.find_all('a', href=re.compile(r"/\d+/\d+/\w+/page\.htm"))    for link in links:        new_url = link['href']        new_full_url = urljoin(page_url, new_url)        new_urls.add(new_full_url)    return new_urlsdef get_new_data(page_url, soup):    res_data = {}    title_node = soup.find('h2', class_='arti-title')    if title_node is None:        return res_data    res_data['title'] = title_node.get_text()    datetime_node = soup.find('span', class_='arti-update')    res_data['datetime'] = datetime_node.get_text()    visitcount_node = soup.find('span', class_='WP_VisitCount')    res_data['visitcount'] = visitcount_node.get_text()    res_data['url'] = page_url    return res_datadef parse(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 = get_new_urls(page_url, soup)    new_data = get_new_data(page_url, soup)    return new_urls, new_data

spider_main

import urls_manager, html_downloader, \    html_parser, html_outputerdef craw(root_url):    count = 1    urls_manager.add_new_url(root_url)    #启动爬虫循环    while urls_manager.has_new_url():        new_url = urls_manager.get_new_url()        print('craw %d : %s' % (count, new_url))        html_cont = html_downloader.download(new_url)        new_urls, new_data = html_parser.parse(new_url, html_cont)        urls_manager.add_new_urls(new_urls)        if new_data:            html_outputer.collect_data(new_data)        if count == 10:            break        count = count + 1    html_outputer.output_html()if __name__ == '__main__':    root_url = 'http://news.zzuli.edu.cn/'    craw(root_url)import urls_manager, html_downloader, \    html_parser, html_outputerdef craw(root_url):    count = 1    urls_manager.add_new_url(root_url)    #启动爬虫循环    while urls_manager.has_new_url():        new_url = urls_manager.get_new_url()        print('craw %d : %s' % (count, new_url))        html_cont = html_downloader.download(new_url)        new_urls, new_data = html_parser.parse(new_url, html_cont)        urls_manager.add_new_urls(new_urls)        if new_data:            html_outputer.collect_data(new_data)        if count == 10:            break        count = count + 1    html_outputer.output_html()if __name__ == '__main__':    root_url = 'http://news.zzuli.edu.cn/'    craw(root_url)

test_64

from bs4 import BeautifulSoupimport rehtml_doc = """
The Dormouse's story
Once upon a time there were three little sisters; and their names wereElsie,Lacie andTillie;and they lived at the bottom of a well.
...
"""soup = BeautifulSoup(html_doc, 'html.parser')print('获取所有链接')links = soup.find_all('a')for link in links:    print(link.name, link['href'], link.get_text())print('获取lacie链接')link_node = soup.find('a', href='http://example.com/lacie')print(link_node.name, link_node['href'], link_node.get_text())print('正则匹配')link_node = soup.find('a', href=re.compile(r'ill'))print(link_node.name, link_node['href'], link_node.get_text())print('获取P段落文字')p_node = soup.find('p', class_='title')print(p_node.name, p_node.get_text())

urls_manager

new_urls = set()old_urls = set()def add_new_url(url):    if url is None:        return    if url not in new_urls and url not in old_urls:        new_urls.add(url)def add_new_urls(urls):    if urls is None or len(urls) == 0:        return    for url in urls:        add_new_url(url)def get_new_url():    new_url = new_urls.pop()    old_urls.add(new_url)    return new_urldef has_new_url():    return len(new_urls) != 0

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