Scrapy初试牛刀

概述1.安装 pip install configparser # 依赖pip install Scrapy 2.官网的一个简单例子 https://docs.scrapy.org/en/latest/intro/overview.html #!/usr/bin/env python# coding=utf-8import scrapyclass QuotesSpider(scrapy

1.安装

pip install configparser  # 依赖pip install Scrapy

2.官网的一个简单例子

https://docs.scrapy.org/en/latest/intro/overview.html

#!/usr/bin/env python# Coding=utf-8import scrapyclass QuotesspIDer(scrapy.SpIDer):    name = 'quotes'    start_urls = ['http://quotes.toscrape.com/tag/humor/']    def parse(self,response):        for quote in response.CSS('div.quote'):            yIEld {                'text': quote.CSS('span.text::text').get(),'author': quote.xpath('span/small/text()').get()            }        next_page = response.CSS('li.next a::attr("href")').get()        if next_page is not None:            yIEld response.follow(next_page,self.parse)

在linux CentOS 6-10下：

$cd$vi quotes_spIDer.py

然后把上面的代码粘上去，:wq保存并退出vi。然后运行这个爬虫。

$scrapy runspIDer quotes_spIDer.py -o ./quotes.Json

跑完后，会在当前目录下生成quotes.Json。

$cat quotes.Json

显示输出文件的内容：

[{"text": "\u201cThe person,be it gentleman or lady,who has not pleasure in a good novel,must be intolerably stupID.\u201d","author": "Jane Austen"},{"text": "\u201cA day without sunshine is like,you kNow,night.\u201d","author": "Steve Martin"},{"text": "\u201cAnyone who thinks sitting in church can make you a Christian must also think that sitting in a garage can make you a car.\u201d","author": "Garrison Keillor"},{"text": "\u201cBeauty is in the eye of the beholder and it may be necessary from time to time to give a stupID or misinformed beholder a black eye.\u201d","author": "Jim Henson"},{"text": "\u201cAll you need is love. But a little chocolate Now and then doesn't hurt.\u201d","author": "Charles M. Schulz"},{"text": "\u201cRemember,we're madly in love,so it's all right to kiss me anytime you feel like it.\u201d","author": "Suzanne Collins"},{"text": "\u201cSome people never go crazy. What truly horrible lives they must lead.\u201d","author": "Charles Bukowski"},{"text": "\u201cThe trouble with having an open mind,of course,is that people will insist on coming along and trying to put things in it.\u201d","author": "Terry Pratchett"},{"text": "\u201cThink left and think right and think low and think high. Oh,the thinks you can think up if only you try!\u201d","author": "Dr. Seuss"},{"text": "\u201cThe reason I talk to myself is because I\u2019m the only one whose answers I accept.\u201d","author": "George Carlin"},{"text": "\u201cI am free of all prejudice. I hate everyone equally. \u201d","author": "W.C. FIElds"},{"text": "\u201cA lady's imagination is very rAPId; it jumps from admiration to love,from love to matrimony in a moment.\u201d","author": "Jane Austen"}]

3.执行过程

3.1.当执行命令

$scrapy runspIDer quotes_spIDer.py -o ./quotes.Json

Scrapy查找定义在quotes_spIDer.py的SpIDer（这里是SpIDer的子类，QuotesspIDer），然后通过爬虫Engine开始运行。

3.2.爬虫入口

在QuotesspIDer里定义的start_urls是爬虫的初始URL列表。爬虫从这个列表中拿到URL，创建Request，得到返回的Response，然后调用默认的回调方法parse，传入的参数就是返回的Response。

3.3.处理响应

在parse方法中，通过css选择器来提取想要的引用元素，用提取到的内容生成一个字典。对于额外的链接，由调度器生成另外的Request，回调方法同样是parse。

总结

以上是内存溢出为你收集整理的Scrapy初试牛刀全部内容，希望文章能够帮你解决Scrapy初试牛刀所遇到的程序开发问题。

如果觉得内存溢出网站内容还不错，欢迎将内存溢出网站推荐给程序员好友。