Python爬虫根据关键词爬取知网论文摘要并保存到数据库中

由于实验室需要一些语料做研究，语料要求是知网上的论文摘要，但是目前最新版的知网爬起来有些麻烦，所以我利用的是知网的另外一个搜索接口

比如下面这个网页：
http://search.cnki.net/Search.aspx?q=肉制品

搜索出来的结果和知网上的结果几乎一样

在这个基础上，我简单看了些网页的结构，很容易就能写出爬取得代码（是最基础的，相当不完善，增加其他功能可自行增加）

网页的结构还是很清晰的

摘要信息也很清晰

我使用的是 pymysql 连接的数据库，效率也还可以
下面直接贴代码：

# -*- coding: utf-8 -*-
import time
import re
import random
import requests
from bs4 import BeautifulSoup
import pymysql

connection = pymysql.connect(host='',
                             user='',
                             password='',
                             db='',
                             port=3306,
                             charset='utf8')  # 注意是utf8不是utf-8

# 获取游标
cursor = connection.cursor()

#url = 'http://epub.cnki.net/grid2008/brief/detailj.aspx?filename=RLGY201806014&dbname=CJFDLAST2018'

#这个headers信息必须包含，否则该网站会将你的请求重定向到其它页面
headers = {
    'Accept':'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8',
    'Accept-Encoding':'gzip, deflate, sdch',
    'Accept-Language':'zh-CN,zh;q=0.8',
    'Connection':'keep-alive',
    'Host':'www.cnki.net',
    'Referer':'http://search.cnki.net/search.aspx?q=%E4%BD%9C%E8%80%85%E5%8D%95%E4%BD%8D%3a%E6%AD%A6%E6%B1%89%E5%A4%A7%E5%AD%A6&rank=relevant&cluster=zyk&val=CDFDTOTAL',
    'Upgrade-Insecure-Requests':'1',
    'User-Agent':'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36'
}

headers1 = {
        'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.143 Safari/537.36'
    }

def get_url_list(start_url):
    depth = 20
    url_list = []
    for i in range(depth):
        try:
            url = start_url + "&p=" + str(i * 15)
            search = requests.get(url.replace('\n', ''), headers=headers1)
            soup = BeautifulSoup(search.text, 'html.parser')
            for art in soup.find_all('div', class_='wz_tab'):
                print(art.find('a')['href'])
                if art.find('a')['href'] not in url_list:
                    url_list.append(art.find('a')['href'])
            print("爬取第" + str(i) + "页成功！")
            time.sleep(random.randint(1, 3))
        except:
            print("爬取第" + str(i) + "页失败！")
    return url_list

def get_data(url_list, wordType):
    try:
        # 通过url_results.txt读取链接进行访问
        for url in url_list:
            i = 1;
            if url == pymysql.NULL or url == '':
                continue
            try:
                html = requests.get(url.replace('\n', ''), headers=headers)
                soup = BeautifulSoup(html.text, 'html.parser')
            except:
                print("获取网页失败")
            try:
                print(url)
                if soup is None:
                    continue
                # 获取标题
                title = soup.find('title').get_text().split('-')[0]
                # 获取作者
                author = ''
                for a in soup.find('div', class_='summary pad10').find('p').find_all('a', class_='KnowledgeNetLink'):
                    author += (a.get_text() + ' ')
                # 获取摘要
                abstract = soup.find('span', id='ChDivSummary').get_text()
                # 获取关键词，存在没有关键词的情况
            except:
                print("部分获取失败")
                pass
            try:
                key = ''
                for k in soup.find('span', id='ChDivKeyWord').find_all('a', class_='KnowledgeNetLink'):
                    key += (k.get_text() + ' ')
            except:
                pass
            print("第" + str(i) + "个url")
            print("【Title】：" + title)
            print("【author】：" + author)
            print("【abstract】：" + abstract)
            print("【key】：" + key)
            # 执行SQL语句
            cursor.execute('INSERT INTO cnki VALUES (NULL, %s, %s, %s, %s, %s)', (wordType, title, author, abstract, key))
            # 提交到数据库执行
            connection.commit()

            print()
        print("爬取完毕")
    finally:
        print()

if __name__ == '__main__':
    try:
        for wordType in {"大肠杆菌", "菌群总落", "胭脂红", "日落黄"}:
            wordType = "肉+" + wordType
            start_url = "http://search.cnki.net/search.aspx?q=%s&rank=relevant&cluster=zyk&val=" % wordType
            url_list = get_url_list(start_url)
            print("开始爬取")
            get_data(url_list, wordType)
            print("一种类型爬取完毕")
        print("全部爬取完毕")
    finally:
        connection.close()

在这里的关键词我简单的选了几个，作为实验，如果爬取的很多，可以写在txt文件里，直接读取就可以，非常方便。