scrapy spider的几种爬取方式实例代码

Python  /  管理员 发布于 5年前   306

本节课介绍了scrapy的爬虫框架，重点说了scrapy组件spider。

spider的几种爬取方式：

1. 爬取1页内容
2. 按照给定列表拼出链接爬取多页
3. 找到‘下一页'标签进行爬取
4. 进入链接，按照链接进行爬取
   

下面分别给出了示例

1.爬取1页内容

#by 寒小阳([email protected])import scrapyclass JulyeduSpider(scrapy.Spider):  name = "julyedu"  start_urls = [    'https://www.julyedu.com/category/index',  ]  def parse(self, response):    for julyedu_class in response.xpath('//div[@class="course_info_box"]'):      print julyedu_class.xpath('a/h4/text()').extract_first()      print julyedu_class.xpath('a/p[@class="course-info-tip"][1]/text()').extract_first()      print julyedu_class.xpath('a/p[@class="course-info-tip"][2]/text()').extract_first()      print response.urljoin(julyedu_class.xpath('a/img[1]/@src').extract_first())      print "\n"      yield {        'title':julyedu_class.xpath('a/h4/text()').extract_first(),        'desc': julyedu_class.xpath('a/p[@class="course-info-tip"][1]/text()').extract_first(),        'time': julyedu_class.xpath('a/p[@class="course-info-tip"][2]/text()').extract_first(),        'img_url': response.urljoin(julyedu_class.xpath('a/img[1]/@src').extract_first())      }

2.按照给定列表拼出链接爬取多页

#by 寒小阳([email protected])import scrapyclass CnBlogSpider(scrapy.Spider):  name = "cnblogs"  allowed_domains = ["cnblogs.com"]  start_urls = [    'http://www.cnblogs.com/pick/#p%s' % p for p in xrange(1, 11)    ]  def parse(self, response):    for article in response.xpath('//div[@class="post_item"]'):      print article.xpath('div[@class="post_item_body"]/h3/a/text()').extract_first().strip()      print response.urljoin(article.xpath('div[@class="post_item_body"]/h3/a/@href').extract_first()).strip()      print article.xpath('div[@class="post_item_body"]/p/text()').extract_first().strip()      print article.xpath('div[@class="post_item_body"]/div[@class="post_item_foot"]/a/text()').extract_first().strip()      print response.urljoin(article.xpath('div[@class="post_item_body"]/div/a/@href').extract_first()).strip()      print article.xpath('div[@class="post_item_body"]/div[@class="post_item_foot"]/span[@class="article_comment"]/a/text()').extract_first().strip()      print article.xpath('div[@class="post_item_body"]/div[@class="post_item_foot"]/span[@class="article_view"]/a/text()').extract_first().strip()      print ""      yield {        'title': article.xpath('div[@class="post_item_body"]/h3/a/text()').extract_first().strip(),        'link': response.urljoin(article.xpath('div[@class="post_item_body"]/h3/a/@href').extract_first()).strip(),        'summary': article.xpath('div[@class="post_item_body"]/p/text()').extract_first().strip(),        'author': article.xpath('div[@class="post_item_body"]/div[@class="post_item_foot"]/a/text()').extract_first().strip(),        'author_link': response.urljoin(article.xpath('div[@class="post_item_body"]/div/a/@href').extract_first()).strip(),        'comment': article.xpath('div[@class="post_item_body"]/div[@class="post_item_foot"]/span[@class="article_comment"]/a/text()').extract_first().strip(),        'view': article.xpath('div[@class="post_item_body"]/div[@class="post_item_foot"]/span[@class="article_view"]/a/text()').extract_first().strip(),      }

3.找到‘下一页'标签进行爬取

import scrapyclass QuotesSpider(scrapy.Spider):  name = "quotes"  start_urls = [    'http://quotes.toscrape.com/tag/humor/',  ]  def parse(self, response):    for quote in response.xpath('//div[@class="quote"]'):      yield {        'text': quote.xpath('span[@class="text"]/text()').extract_first(),        'author': quote.xpath('span/small[@class="author"]/text()').extract_first(),      }    next_page = response.xpath('//li[@class="next"]/@herf').extract_first()    if next_page is not None:      next_page = response.urljoin(next_page)      yield scrapy.Request(next_page, callback=self.parse)

4.进入链接，按照链接进行爬取

#by 寒小阳([email protected])import scrapyclass QQNewsSpider(scrapy.Spider):  name = 'qqnews'  start_urls = ['http://news.qq.com/society_index.shtml']  def parse(self, response):    for href in response.xpath('//*[@id="news"]/div/div/div/div/em/a/@href'):      full_url = response.urljoin(href.extract())      yield scrapy.Request(full_url, callback=self.parse_question)  def parse_question(self, response):    print response.xpath('//div[@class="qq_article"]/div/h1/text()').extract_first()    print response.xpath('//span[@class="a_time"]/text()').extract_first()    print response.xpath('//span[@class="a_catalog"]/a/text()').extract_first()    print "\n".join(response.xpath('//div[@id="Cnt-Main-Article-QQ"]/p[@class="text"]/text()').extract())    print ""    yield {      'title': response.xpath('//div[@class="qq_article"]/div/h1/text()').extract_first(),      'content': "\n".join(response.xpath('//div[@id="Cnt-Main-Article-QQ"]/p[@class="text"]/text()').extract()),      'time': response.xpath('//span[@class="a_time"]/text()').extract_first(),      'cate': response.xpath('//span[@class="a_catalog"]/a/text()').extract_first(),    }

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