简单的网络scrapy爬虫示例代码

# -*- coding: utf-8 -*-
import scrapy


# scrapy genspider itcast "itcast.cn"
# scrapy startproject mySpider


class ITcastItem(scrapy.Item):
    name = scrapy.Field()
    title = scrapy.Field()
    info = scrapy.Field()


class ItcastSpider(scrapy.Spider):
    name = 'itcast'
    allowed_domains = ['itcast.cn']
    start_urls = ["http://www.itcast.cn/channel/teacher.shtml", ]

    # scrapy crawl itcast
    # scrapy crawl itcast -o teachers.csv
    # scrapy crawl itcast -o teachers.json
    # scrapy crawl itcast -o teachers.jsonl
    # scrapy crawl itcast -o teachers.xml
    def parse(self, response):
        filename = "teacher.html"
        open(filename, 'wb').write(response.body)
        context = response.xpath('/html/head/title/text()')
        title = context.extract_first()
        print(title)
        # 存放老师信息的集合
        items = []

        for each in response.xpath("//div[@class='li_txt']"):
            # 将我们得到的数据封装到一个 `ItcastItem` 对象
            item = ITcastItem()
            # extract()方法返回的都是unicode字符串
            name = each.xpath("h3/text()").extract()
            title = each.xpath("h4/text()").extract()
            info = each.xpath("p/text()").extract()

            # xpath返回的是包含一个元素的列表
            item['name'] = name[0]
            item['title'] = title[0]
            item['info'] = info[0]

            items.append(item)

        # 直接返回最后数据
        return items