scrapy簡單學習

學習網站：scrapy入門教程

1.建立項目：cmd打開scrapy所在位置，輸入命令

scrapy startproject tutorial

2.定義item：編輯item.py,對您想要採集的數據類型進行定義。例如：

import scrapy

class DmozItem(scrapy.Item):
    title = scrapy.Field()
    link = scrapy.Field()
    desc = scrapy.Field()

3.編寫爬蟲：在spiders的文件下新建一個domz_spider.py文件，代碼以下：

import scrapy

from tutorial.items import DmozItem

class DmozSpider(scrapy.Spider):
    name = "dmoz"
    allowed_domains = ["dmoz.org"]
    start_urls = [
        "http://www.dmoz.org/Computers/Programming/Languages/Python/Books/",
        "http://www.dmoz.org/Computers/Programming/Languages/Python/Resources/"
    ]

    def parse(self, response):
        for sel in response.xpath('//ul/li'):
            item = DmozItem()
            item['title'] = sel.xpath('a/text()').extract()
            item['link'] = sel.xpath('a/@href').extract()
            item['desc'] = sel.xpath('text()').extract()
            yield item

4.啓動爬蟲：在cmd的命令行轉至spiders的根目錄下，輸入命令

scrapy crawl dmoz

5.保存數據：

scrapy crawl dmoz -o items.json

或者

scrapy crawl dmoz -o items.csv