Python爬虫练习一

Python爬虫练习一

一个简单的基于scrapy框架爬虫的练习
GItHub：https://github.com/P-jinsan/doubanbook

环境

Pycharm、Python3.8、谷歌浏览器

要求

1. 网址：豆瓣读书

2. 要求：获取每本书的标题、作者、评分
   

3. 将获取的信息输出到一个excle文件中

注意

需要获取的内容可能不只是一页

过程

1. 文件目录,以下只列出该练习需要用到的文件
   

2. dbbook.py

import scrapy
import re
from doubanbook.items import DoubanbookItem
class DbbookSpider(scrapy.Spider):
    name = 'dbbook'
    #allowed_domains = ['https://www.douban.com/doulist/1264675/']
    start_urls = ['https://www.douban.com/doulist/1264675/']

    def parse(self, response):
        item = DoubanbookItem() # 引入 item
        selector = scrapy.Selector(response) # 使用Selector选择器 xpath
        books = selector.xpath('//div[@class="bd doulist-subject"]') # 通过控制台查看路径，选择所有class="bd doulist-subject" 的div
        
        for each in books: # 遍历查看，筛选出需要的信息
            title = each.xpath('div[@class="title"]/a/text()').extract()[0] 
            rate = each.xpath('div[@class="rating"]/span[@class="rating_nums"]/text()').extract()[0]
            author = re.search('
(.*?), each.extract(), re.S).group(1) #作者这里采用的是正则，原因为xpath会获取到多余的信息 例如出版社等
            title = title.replace(' ', '').replace('\n', '') # 去除空格和换行
            author = author.replace(' ', '').replace('\n', '')
            item['title'] = title # 存入item
            item['rate'] = rate
            item['author'] = author
            #print('标题:' + title)
            #print('评分:' + rate)
            #print('作者:' + author)
            #print('')
            yield item # 回溯
            
            # 获取下一页地址（若存在下一页）原理同上，只是获取信息为链接
            nextPage = selector.xpath('//span[@class="next"]/link/@href').extract()
            if nextPage:
                next = nextPage[0]
                # print(next)
                yield scrapy.http.Request(next,callback=self.parse) # 重新获取该页面

3. items.py

import scrapy

class DoubanbookItem(scrapy.Item):
    title = scrapy.Field()
    rate = scrapy.Field()
    author = scrapy.Field()

4. settings.py

BOT_NAME = 'doubanbook'

SPIDER_MODULES = ['doubanbook.spiders']
NEWSPIDER_MODULE = 'doubanbook.spiders'
USER_AGENT = 'Mozilla/5.0 (Windows NT 6.3; WOW64; rv:45.0) Gecko/20100101 Firefox/45.0'
FEED_URI = u'file:///d://doubanbooks.csv' #即存入d盘 doubanbooks.csv文件中
FEED_FORMAT = 'CSV'
ROBOTSTXT_OBEY = True

5. main.py

from scrapy import cmdline
cmdline.execute("scrapy crawl dbbook".split())#运行爬虫

结束

1. 运行main.py文件爬虫即可运行
2. 运行结束后文件可能出现乱码，如下图。需要将其编码修改为UTF-8-Bom编码（个人采用notepad++）
   

3. 网页显示存在648本，实际爬出来只有631本