爬虫_scrapy_多级页面的数据爬取

本案例以爬取电影天堂第一级页面的电影名称和点击链接后二级页面的img地址，并将第一级的名称和第二级页面的图片地址一起写入json文件，涉及到多级页面数据的组合。

创建项目和页面命令这里就不说了，可以参考我之前的文章，这里主要说明核心代码。

1.spiders下的mv.py代码

import scrapy
from scrapy_movie.items import ScrapyMovieItem
# 电影天堂多页数据下载
class MvSpider(scrapy.Spider):
    name = 'mv'
    allowed_domains = ['www.dytt8.net']
    start_urls = ['https://www.dytt8.net/html/gndy/china/index.html']

    def parse(self, response):
        # 要第一页的名字和第二页的图片
        a_list = response.xpath('//div[@class="co_content8"]//td[2]//a[2]')
        for a in a_list:
            # 获取第一页的name 和 要点击的连接
            name = a.xpath('./text()').extract_first()
            href = a.xpath('./@href').extract_first()

            # 第二页的地址
            url = 'https://www.dytt8.net'+href
            # 对第二页的链接发起访问
            # 调用点击的页面发起请求，并将已经获取的name通过meta字典传递给parse_second方法
            yield scrapy.Request(url=url,callback=self.parse_second,meta={'name':name})

    def parse_second(self,response):
        # 点击进入里边页面的图片地址
        # 注意 如果拿不到数据的情况下，一定检查你的xpath语法是否正确
        src = response.xpath('//div[@id="Zoom"]//img/@src').extract_first()
        print(src)
        # 接收meta传递过来的参数值
        name = response.meta['name']
        # 创建解析对象
        movie = ScrapyMovieItem(name=name,src=src)
        # 返回给管道
        yield movie

2.items.py数据结构

# Define here the models for your scraped items
#
# See documentation in:
# https://docs.scrapy.org/en/latest/topics/items.html

import scrapy

# 解析的数据结构
class ScrapyMovieItem(scrapy.Item):
    # define the fields for your item here like:
    # name = scrapy.Field()
    name = scrapy.Field()
    src = scrapy.Field()
    pass

3.pipelines.py管道

# Define your item pipelines here
#
# Don't forget to add your pipeline to the ITEM_PIPELINES setting
# See: https://docs.scrapy.org/en/latest/topics/item-pipeline.html


# useful for handling different item types with a single interface
from itemadapter import ItemAdapter

# 管道
class ScrapyMoviePipeline:
    # 在爬虫文件开始的之前就执行这个方法
    def open_spider(self,spider):
        self.fp = open('movie.json','w',encoding='utf-8')
    # item就是yield后面的对象
    def process_item(self, item, spider):
        # 数据处理，写文件
        # write方法只能写字符串，需要强转
        self.fp.write(str(item))
        return item
    # 在爬虫文件执行完成后，执行的方法
    def close_spider(self,spider):
        self.fp.close()

4.settings.py配置

# Scrapy settings for scrapy_movie project
#
# For simplicity, this file contains only settings considered important or
# commonly used. You can find more settings consulting the documentation:
#
#     https://docs.scrapy.org/en/latest/topics/settings.html
#     https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
#     https://docs.scrapy.org/en/latest/topics/spider-middleware.html

BOT_NAME = 'scrapy_movie'

SPIDER_MODULES = ['scrapy_movie.spiders']
NEWSPIDER_MODULE = 'scrapy_movie.spiders'


# Crawl responsibly by identifying yourself (and your website) on the user-agent
#USER_AGENT = 'scrapy_movie (+http://www.yourdomain.com)'

# Obey robots.txt rules
ROBOTSTXT_OBEY = True

# Configure maximum concurrent requests performed by Scrapy (default: 16)
#CONCURRENT_REQUESTS = 32

# Configure a delay for requests for the same website (default: 0)
# See https://docs.scrapy.org/en/latest/topics/settings.html#download-delay
# See also autothrottle settings and docs
#DOWNLOAD_DELAY = 3
# The download delay setting will honor only one of:
#CONCURRENT_REQUESTS_PER_DOMAIN = 16
#CONCURRENT_REQUESTS_PER_IP = 16

# Disable cookies (enabled by default)
#COOKIES_ENABLED = False

# Disable Telnet Console (enabled by default)
#TELNETCONSOLE_ENABLED = False

# Override the default request headers:
#DEFAULT_REQUEST_HEADERS = {
#   'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
#   'Accept-Language': 'en',
#}

# Enable or disable spider middlewares
# See https://docs.scrapy.org/en/latest/topics/spider-middleware.html
#SPIDER_MIDDLEWARES = {
#    'scrapy_movie.middlewares.ScrapyMovieSpiderMiddleware': 543,
#}

# Enable or disable downloader middlewares
# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
#DOWNLOADER_MIDDLEWARES = {
#    'scrapy_movie.middlewares.ScrapyMovieDownloaderMiddleware': 543,
#}

# Enable or disable extensions
# See https://docs.scrapy.org/en/latest/topics/extensions.html
#EXTENSIONS = {
#    'scrapy.extensions.telnet.TelnetConsole': None,
#}

# Configure item pipelines
# See https://docs.scrapy.org/en/latest/topics/item-pipeline.html
ITEM_PIPELINES = {
   'scrapy_movie.pipelines.ScrapyMoviePipeline': 300,
}

# Enable and configure the AutoThrottle extension (disabled by default)
# See https://docs.scrapy.org/en/latest/topics/autothrottle.html
#AUTOTHROTTLE_ENABLED = True
# The initial download delay
#AUTOTHROTTLE_START_DELAY = 5
# The maximum download delay to be set in case of high latencies
#AUTOTHROTTLE_MAX_DELAY = 60
# The average number of requests Scrapy should be sending in parallel to
# each remote server
#AUTOTHROTTLE_TARGET_CONCURRENCY = 1.0
# Enable showing throttling stats for every response received:
#AUTOTHROTTLE_DEBUG = False

# Enable and configure HTTP caching (disabled by default)
# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html#httpcache-middleware-settings
#HTTPCACHE_ENABLED = True
#HTTPCACHE_EXPIRATION_SECS = 0
#HTTPCACHE_DIR = 'httpcache'
#HTTPCACHE_IGNORE_HTTP_CODES = []
#HTTPCACHE_STORAGE = 'scrapy.extensions.httpcache.FilesystemCacheStorage'