爬虫库

使用简单的requests库，这是一个阻塞的库，速度比较慢。
解析使用XPATH表达式
总体采用类的形式

多线程

使用concurrent.future并发模块，建立线程池，把future对象扔进去执行即可实现并发爬取效果

数据存储

使用Python ORM sqlalchemy保存到数据库，也可以使用自带的csv模块存在CSV中。

API接口

因为API接口存在数据保护情况，一个电影的每一个分类只能抓取前25页，全部评论、好评、中评、差评所有分类能爬100页，每页有20个数据，即最多为两千条数据。

因为时效性原因，不保证代码能爬到数据，只是给大家一个参考思路，上代码：

  1 from datetime import datetime
  2 import random
  3 import csv
  4 from concurrent.futures import ThreadPoolExecutor, as_completed
  5 
  6 from lxml import etree
  7 import pymysql
  8 import requests
  9 
 10 from models import create_session, Comments
 11 
 12 #随机UA
 13 USERAGENT = [
 14     ‘Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.1 (KHTML, like Gecko) Chrome/14.0.835.163 Safari/535.1‘,
 15     ‘Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.103 Safari/537.36‘,
 16     ‘Mozilla/5.0 (Windows NT 6.1; WOW64; rv:6.0) Gecko/20100101 Firefox/6.0‘,
 17     ‘Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/534.50 (KHTML, like Gecko) Version/5.1 Safari/534.50‘,
 18     ‘Opera/9.80 (Windows NT 6.1; U; zh-cn) Presto/2.9.168 Version/11.50‘,
 19     ‘Mozilla/5.0 (Windows; U; Windows NT 6.1; ) AppleWebKit/534.12 (KHTML, like Gecko) Maxthon/3.0 Safari/534.12‘
 20 ]
 21 
 22 
 23 class CommentFetcher:
 24     headers = {‘User-Agent‘: ‘‘}
 25     cookie = ‘‘
 26     cookies = {‘cookie‘: cookie}
 27     # cookie为登录后的cookie，需要自行复制
 28     base_node = ‘//div[@class="comment-item"]‘
 29 
 30 
 31     def __init__(self, movie_id, start, type=‘‘):
 32         ‘‘‘
 33         :type: 全部评论：‘‘， 好评：h 中评：m 差评：l
 34         :movie_id: 影片的ID号
 35         :start: 开始的记录数，0-480
 36         ‘‘‘
 37         self.movie_id = movie_id
 38         self.start = start
 39         self.type = type
 40         self.url = ‘https://movie.douban.com/subject/{id}/comments?start={start}&limit=20&sort=new_score\&status=P&percent_type={type}&comments_only=1‘.format(
 41             id=str(self.movie_id),
 42             start=str(self.start),
 43             type=self.type
 44         )
 45         #创建数据库连接
 46         self.session = create_session()
 47 
 48     #随机useragent
 49     def _random_UA(self):
 50         self.headers[‘User-Agent‘] = random.choice(USERAGENT)
 51 
 52 
 53     #获取api接口，使用get方法，返回的数据为json数据，需要提取里面的HTML
 54     def _get(self):
 55         self._random_UA()
 56         res = ‘‘
 57         try:
 58             res = requests.get(self.url, cookies=self.cookies, headers=self.headers)
 59             res = res.json()[‘html‘]
 60         except Exception as e:
 61             print(‘IP被封，请使用代理IP‘)
 62         print(‘正在获取{} 开始的记录‘.format(self.start))
 63         return res
 64 
 65     def _parse(self):
 66         res = self._get()
 67         dom = etree.HTML(res)
 68 
 69         #id号
 70         self.id = dom.xpath(self.base_node + ‘/@data-cid‘)
 71         #用户名
 72         self.username = dom.xpath(self.base_node + ‘/div[@class="avatar"]/a/@title‘)
 73         #用户连接
 74         self.user_center = dom.xpath(self.base_node + ‘/div[@class="avatar"]/a/@href‘)
 75         #点赞数
 76         self.vote = dom.xpath(self.base_node + ‘//span[@class="votes"]/text()‘)
 77         #星级
 78         self.star = dom.xpath(self.base_node + ‘//span[contains(@class,"rating")]/@title‘)
 79         #发表时间
 80         self.time = dom.xpath(self.base_node + ‘//span[@class="comment-time "]/@title‘)
 81         #评论内容 所有span标签class名为short的节点文本
 82         self.content = dom.xpath(self.base_node + ‘//span[@class="short"]/text()‘)
 83 
 84     #保存到数据库
 85     def save_to_database(self):
 86         self._parse()
 87         for i in range(len(self.id)):
 88             try:
 89                 comment = Comments(
 90                     id=int(self.id[i]),
 91                     username=self.username[i],
 92                     user_center=self.user_center[i],
 93                     vote=int(self.vote[i]),
 94                     star=self.star[i],
 95                     time=datetime.strptime(self.time[i], ‘%Y-%m-%d %H:%M:%S‘),
 96                     content=self.content[i]
 97                 )
 98 
 99                 self.session.add(comment)
100                 self.session.commit()
101                 return ‘finish‘
102 
103 
104             except pymysql.err.IntegrityError as e:
105                 print(‘数据重复，不做任何处理‘)
106 
107             except Exception as e:
108                 #数据添加错误，回滚
109                 self.session.rollback()
110 
111             finally:
112                 #关闭数据库连接
113                 self.session.close()
114 
115     #保存到csv
116     def save_to_csv(self):
117         self._parse()
118         f = open(‘comment.csv‘, ‘w‘, encoding=‘utf-8‘)
119         csv_in = csv.writer(f, dialect=‘excel‘)
120         for i in range(len(self.id)):
121             csv_in.writerow([
122                 int(self.id[i]),
123                 self.username[i],
124                 self.user_center[i],
125                 int(self.vote[i]),
126                 self.time[i],
127                 self.content[i]
128             ])
129         f.close()
130 
131 
132 if __name__ == ‘__main__‘:
133     with ThreadPoolExecutor(max_workers=4) as executor:
134         futures = []
135         for i in [‘‘, ‘h‘, ‘m‘, ‘l‘]:
136             for j in range(25):
137                 fetcher = CommentFetcher(movie_id=26266893, start=j * 20, type=i)
138                 futures.append(executor.submit(fetcher.save_to_csv))
139 
140         for f in as_completed(futures):
141             try:
142                 res = f.done()
143                 if res:
144                     ret_data = f.result()
145                     if ret_data == ‘finish‘:
146                         print(‘{} 成功保存数据‘.format(str(f)))
147             except Exception as e:
148                 f.cancel()