python爬虫scrapy基于CrawlSpider类的全站数据爬取示例解析

link = LinkExtractor(
# Items只能是一个正则表达式,会提取当前页面中满足该"正则表达式"的url	
　 allow=r'Items/'
)

import scrapy
# 导入相关的包
from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import CrawlSpider, Rule

class TextSpider(CrawlSpider):
 name = 'text'
 allowed_domains = ['www.xxx.com']
 start_urls = ['http://www.xxx.com/']

# 链接提取器,从接受到的response对象中,根据item正则表达式提取页面中的链接
	link = LinkExtractor(allow=r'Items/')
	link2 = LinkExtractor(allow=r'Items/')
# 规则解析器,根据callback将链接提取器提取到的链接进行数据解析
# follow为true,则表示将链接提取器继续作用到链接提取器所提取到的链接页面中
# 故:在我们提取多页数据时,若第一页对应的网页中包含了第2,3,4,5页的链接,
# 当跳转到第5页时,第5页又包含了第6,7,8,9页的链接,
# 令follow=True,就可以持续作用,从而提取到所有页面的链接
 rules = (Rule(link, callback='parse_item', follow=True),
 		Rule(link2,callback='parse_content',follow=False))
 # 链接提取器link使用parse_item解析数据
	def parse_item(self, response):
 item = {}
 
 yield item
 # 链接提取器link2使用parse_content解析数据
	def parse_content(self, response):
		item = {}
		
		yield item

scrapy genspider crawl -t spiderName www.xxx.com 

import scrapy
from scrapy.linkextractors import LinkExtractor

from scrapy.spiders import CrawlSpider, Rule
from gushiPro.items import GushiproItem,ContentItem

class GushiSpider(CrawlSpider):
 name = 'gushi'
 #allowed_domains = ['www.xxx.com']
 start_urls = ['https://www.gushiwen.org/']

 # 链接提取器:只能使用正则表达式，提取当前页面的满足allow条件的链接
 link = LinkExtractor(allow=r'/default_\d+\.aspx')

 # 链接提取器，提取所有标题对应的详情页url
 content_link = LinkExtractor(allow=r'cn/shiwenv_\w+\.aspx')
 rules = (
 # 规则解析器，需要解析所有的页面，所有follow=True
 Rule(link, callback='parse_item', follow=True),

 # 不需要写follow，因为我们只需要解析详情页中的数据，而不是详情页中的url
 Rule(content_link, callback='content_item'),
 )

 # 解析当前页面的标题
 def parse_item(self, response):
 p_list = response.xpath('//div[@class="sons"]/div[1]/p[1]')

 for p in p_list:
 title = p.xpath('./a//text()').extract_first()
 item = GushiproItem()
 item['title'] = title
 yield item
 
 # 解析详情页面的标题和内容
 def content_item(self,response):
 # //div[@id="sonsyuanwen"]/div[@class="cont"]/div[@class="contson"]
 # 解析详情页面的内容
 content = response.xpath('//div[@id="sonsyuanwen"]/div[@class="cont"]/div[@class="contson"]//text()').extract()
 content = "".join(content)
 # # 解析详情页面的标题
 title = response.xpath('//div[@id="sonsyuanwen"]/div[@class="cont"]/h1/text()').extract_first()
 # print("title:"+title+"\ncontent:"+content)
 item = ContentItem()
 item["content"] = content
 item["title"] = title
 # 将itme对象传给管道
 yield item

import scrapy

# 不同的item类是独立的，他们可以创建不同的item对象
class GushiproItem(scrapy.Item):
 # define the fields for your item here like:
 # name = scrapy.Field()
 title = scrapy.Field()

class ContentItem(scrapy.Item):
 title = scrapy.Field()
 content = scrapy.Field()

from itemadapter import ItemAdapter

class GushiproPipeline:
 def __init__(self):
 self.fp = None

 def open_spider(self,spider):
 self.fp = open("gushi.txt",'w',encoding='utf-8')
 print("开始爬虫")

 def process_item(self, item, spider):
 # 从详情页获取标题和内容，所以需要判断爬虫文件中传来的item是什么类的item
 # item.__class__.__name__判断属于什么类型的item
 if item.__class__.__name__ == "ContentItem":
 content = "《"+item['title']+"》",item['content']
 content = "".join(content) 
 print(content)
 self.fp.write(content)
 return item

 def close_spider(self,spider):
 self.fp.close()
 print("结束爬虫")