python网络爬虫 CrawlSpider使用详解

# spider文件import scrapyfrom scrapy.linkextractors import LinkExtractorfrom scrapy.spiders import CrawlSpider, Ruleclass ChoutiSpider(CrawlSpider):  name = 'chouti'  # allowed_domains = ['www.xxx.com']  start_urls = ['https://dig.chouti.com/1']  # 连接提取器：从起始url对应的页面中提取符合规则的所有连接；allow=正则表达式  # 正则为空的话，提取页面中所有连接  link = LinkExtractor(allow=r'/d+')  rules = (    # 规则解析器:将连接提取器提取到的连接对应的页面源码进行指定规则的解析    # Rule自动发送对应链接的请求    Rule(link, callback='parse_item', follow=True),    # follow：True 将连接提取器 继续 作用到 连接提取器提取出来的连接 对应的页面源码中  )  def parse_item(self, response):    item = {}    #item['domain_id'] = response.xpath('//input[@id="sid"]/@value').get()    #item['name'] = response.xpath('//div[@id="name"]').get()    #item['description'] = response.xpath('//div[@id="description"]').get()    return item

# 1.spider文件import scrapyfrom scrapy.linkextractors import LinkExtractorfrom scrapy.spiders import CrawlSpider, Rulefrom sunLineCrawl.items import SunlinecrawlItem,ContentItemclass SunSpider(CrawlSpider):  name = 'sun'  # allowed_domains = ['www.xxx.com']  start_urls = ['http://wz.sun0769.com/index.php/question/questionType?type=4&page=']  link = LinkExtractor(allow=r'type=4&page=/d+') # 提取页码连接  link1 = LinkExtractor(allow=r'question/2019/d+//d+/.shtml') # 提取详情页连接  rules = (    Rule(link, callback='parse_item', follow=False),    Rule(link1, callback='parse_detail'),  )  # 解析出标题和网友名称数据  def parse_item(self, response):    tr_list = response.xpath('//*[@id="morelist"]/div/table[2]//tr/td/table//tr')    for tr in tr_list:      title = tr.xpath('./td[2]/a[2]/text()').extract_first()      net_friend = tr.xpath('./td[4]/text()').extract_first()      item = SunlinecrawlItem()      item['title'] = title      item['net_friend'] = net_friend      yield item  # 解析出新闻的内容  def parse_detail(self,response):    content = response.xpath('/html/body/div[9]/table[2]//tr[1]/td/div[2]//text()').extract()    content = ''.join(content)    item = ContentItem()    item['content'] = content    yield item--------------------------------------------------------------------------------# 2.items文件import scrapyclass SunlinecrawlItem(scrapy.Item):  title = scrapy.Field()  net_friend = scrapy.Field()class ContentItem(scrapy.Item):  content = scrapy.Field()--------------------------------------------------------------------------------# 3.pipelines文件class SunlinecrawlPipeline(object):  def process_item(self, item, spider):    # 确定接受到的item是什么类型（Content/Sunlinecrawl）    if item.__class__.__name__ == 'SunlinecrawlItem':      print(item['title'],item['net_friend'])    else:      print(item['content'])    return item--------------------------------------------------------------------------------# 4.setting文件BOT_NAME = 'sunLineCrawl'SPIDER_MODULES = ['sunLineCrawl.spiders']NEWSPIDER_MODULE = 'sunLineCrawl.spiders'LOG_LEVEL = 'ERROR'USER_AGENT = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.132 Safari/537.36'ROBOTSTXT_OBEY = FalseITEM_PIPELINES = {  'sunLineCrawl.pipelines.SunlinecrawlPipeline': 300,}