python爬取中国知网（中国优秀硕士学位论文数据库）
笔者这几天受团队任务安排，需要写一份儿关于知网（中国优秀硕士学位论文数据库 入口：http://gb.oversea.cnki.net/kns55/brief/result.aspx?dbPrefix=CMFD
）的代码，主要是爬取论文的作者信息、论文副标题、学位授予年度、学校、引用频次等，例如在关键词搜索一下医疗保险：
表格的相关信息都可以爬取，点进每一篇文章以后，对应的关键词、副标题信息也可以爬取，只是笔者此次不需要设计下载原文，所以没有写相关代码，但是整个分析格式是一样的，可以根据关键词的爬取方式去寻找下载的url。对于这个内容的爬取，似乎对于访问的限制不太严格，笔者基本不考虑sleep时间,先贴出代码：
# -*- coding:utf-8 -*-
__author__ = 'TengYu'
import requests
import re
from lxml import etree
import json
import time
import xlwt
import sys
reload(sys)
sys.setdefaultencoding('utf8')
headers = {
'User-agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:55.0) Gecko/20100101 Firefox/55.0',
'Cookie':'Your-cookie'
}
class PageList(object):
def __init__(self,maxpage):
self.maxpage = maxpage
def getUrl(self):
f1 = open("title_4_4.txt",'w')
f2 = open("subtitle.txt",'w')
f3 = open("keywords_4_4.txt",'w')
excel = xlwt.Workbook(encoding='utf-8')
sheet = excel.add_sheet('sheet1')
sheet.write(0, 0, '论文中文题目')
sheet.write(0, 1, '论文作者')
sheet.write(0, 2, '作者学校')
sheet.write(0, 3, '学位授予年度')
sheet.write(0, 4, '下载频次')
sheet.write(0, 5, '引用频次')
begin = 6
while begin < 18:
sheet.write(0, begin, '关键词'+str(begin - 6))
begin += 1
while begin < 25:
sheet.write(0, begin, '副标题'+ str(begin - 18))
begin += 1
firstPage = 200
try:
tempurl = " "
num = 0
while firstPage < self.maxpage:
tempurl = "http://gb.oversea.cnki.net/kns55/brief/brief.aspx?curpage="+str(firstPage)+"&RecordsPerPage=20&QueryID=2&ID=&turnpage=1&tpagemode=L&dbPrefix=CMFD&Fields=&DisplayMode=listmode&PageName=ASP.brief_result_aspx&sKuaKuID=2"
response = requests.get(tempurl, headers=headers).content
selector = etree.HTML(response)
trs = selector.xpath("//tr")
firstTds = 11
# print(len(trs))
print("已经抓取"+str(num)+"条数据")
while firstTds < 51:
num = num + 1
tr = trs[firstTds]
td = tr.xpath(".//td")
titletd = td[2]
titlehref = titletd.xpath(".//a/@href")
# print(titlehref)
# print(titletd.xpath("string(.)"))
href = str(titlehref[0])
# print(href) #获取论文详细内容链接
detailurl = "http://gb.oversea.cnki.net" + href
print(detailurl)
authortd = td[3] # 获取作者信息
schooltd = td[4] # 获取学校信息
yeartd = td[5] # 获取年份信息
yinyongtd = td[6] # 获取引用次数信息
xiazaitd = td[7] # 获取下载次数信息
author = str(authortd.xpath("string(.)").encode('utf-8'))
school = str(schooltd.xpath("string(.)").encode('utf-8'))
year = str(yeartd.xpath("string(.)").encode('utf-8'))
yinyong = "0"
xiazai = "0"
yinyongs = str(yinyongtd.xpath("string(.)").encode('utf-8'))
xiazais = str(xiazaitd.xpath("string(.)").encode('utf-8'))
if yinyongs.isspace():
yinyong = "0"
else:
yinyong = yinyongs.replace(' ', '')
if xiazais.isspace():
xiazai = "0"
else:
xiazai = xiazais.replace(' ', '')
firstTds += 2
# 获取具体数据信息，访问构造的detailurl
detail = requests.get(detailurl, headers=headers).content
sel = etree.HTML(detail)
divs = sel.xpath("//div[@id='main']")
title = divs[0].xpath("//div[@id='title']")[0]
span = title.xpath("//h1//span")[0]
st = str(span.xpath("string(.)").encode('utf-8'))
print(st) # 论文题目
divs = sel.xpath(".//div[@class='summary pad10']")[0]
detailinfo = str(divs.xpath("string(.)").encode('utf-8'))
ps = divs.xpath(".//p")
f1.write(st+"\n")
sheet.write(num, 0, st)
sheet.write(num, 1, author)
sheet.write(num, 2, school)
sheet.write(num, 3, year)
sheet.write(num, 4, xiazai)
sheet.write(num, 5, yinyong)
try:
keywordsdiv = sel.xpath(".//div[@class='keywords']")[0]
span = keywordsdiv.xpath(".//span[@id='ChDivKeyWord']")[0]
hrefs = span.xpath(".//a")
i = 0
first = 6
while i < len(hrefs):
words = str(hrefs[i].xpath("string(.)").encode('utf-8'))
print(words)
f3.write(words+"\n")
sheet.write(num, first, words)
first += 1
i += 1
except Exception as es:
print(es)
try:
if u'副题名' in detailinfo:
index = detailinfo.find('【副题名】')
loc = index + 15
then = 18
while detailinfo[loc] != '【':
subtitile = ""
while detailinfo[loc] != ' ' and detailinfo[loc] != ',':
subtitile += detailinfo[loc]
loc += 1
sheet.write(num, then, subtitile)
f2.write(subtitile + "\n")
then += 1
except Exception as es:
print(es)
time.sleep(1)
firstPage += 1
time.sleep(5)
except Exception as es:
print (es)
excel.save("filename.xls")
pass
pagelist = PageList(270)
pagelist.getUrl()
笔者当初大概看了一下，好像搜索出来的那个表格的话，第一页和后面的页数的格式不太一样，所以就从第二页开始爬的，第一页的代码有兴趣的读者可以自行完成（当然也可能一样，只是我没仔细看，因为当时是上午布置任务，下午四点前提交数据，所以就省略过去了）在你完成相关搜索以后，代码所分析的url（从第二页开始）其实是“http://gb.oversea.cnki.net/kns55/brief/brief.aspx?curpage=3&RecordsPerPage=20&QueryID=3&ID=&turnpage=1&tpagemode=L&dbPrefix=CMFD&Fields=&DisplayMode=listmode&PageName=ASP.brief_result_aspx&sKuaKuID=3”，至于怎么分析这个数据是从哪个链接获取的，比较简单，就不在这里介绍了，但是提醒注意的是笔者中途因为有点事儿，断了一下电脑，结果发现怎么都爬不下来了，一开始以为是代码的问题，最后才发现是上面这个url中的"QueryID和sKuqKuID"发生了改变，从3变成了2，所以大家如果出现这种情况，一定记得再去数据获取的url找一下这值，改成正确的一下。整个过程并不难理解，至于后面那个怎么查找具体的关键词之类的，建议大家可以打开一个所有信息（包括关键词，副标题）的论文的源代码后，用个h5开发工具将代码拷贝过去分析一下标签就行了，笔者这里不再赘述。
尊重原作，转载请注明，转载自：https://blog.csdn.net/kr2563