本文的爬虫教程分为四部：
1.从哪爬 where
2.爬什么 what
3.怎么爬 how
4.爬了之后信息如何保存 save
一、从哪爬
三国演义
二、爬什么
三国演义全文
三、怎么爬
在Chrome页面打开F12，就可以发现文章内容在节点
<p id="con" class="bookyuanjiao">
只要找到这个节点，然后把内容写入到一个html文件即可。
content = soup.find("p", {"class": "bookyuanjiao", "id": "con"})四、爬了之后如何保存
主要就是拿到内容，拼接到一个html文件，然后保存下来就可以了。
#!usr/bin/env
# -*-coding:utf-8 -*-
import urllib2
import os
from bs4 import BeautifulSoup as BS
import locale
import sys
from lxml import etree
import re
reload(sys)
sys.setdefaultencoding('gbk')
sub_folder = os.path.join(os.getcwd(), "sanguoyanyi")
if not os.path.exists(sub_folder):
os.mkdir(sub_folder)
path = sub_folder
# customize html as head of the articles
input = open(r'0.html', 'r')
head = input.read()
domain = 'http://www.shicimingju.com/book/sanguoyanyi.html'
t = domain.find(r'.html')
new_domain = '/'.join(domain.split("/")[:-2])
first_chapter_url = domain[:t] + "/" + str(1) + '.html'
print first_chapter_url
# Get url if chapter lists
req = urllib2.Request(url=domain)
resp = urllib2.urlopen(req)
html = resp.read()
soup = BS(html, 'lxml')
chapter_list = soup.find("p", {"class": "bookyuanjiao", "id": "mulu"})
sel = etree.HTML(str(chapter_list))
result = sel.xpath('//li/a/@href')
for each_link in result:
each_chapter_link = new_domain + "/" + each_link
print each_chapter_link
req = urllib2.Request(url=each_chapter_link)
resp = urllib2.urlopen(req)
html = resp.read()
soup = BS(html, 'lxml')
content = soup.find("p", {"class": "bookyuanjiao", "id": "con"})
title = soup.title.text
title = title.split(u'_《三国演义》_诗词名句网')[0]
html = str(content)
html = head + html + "