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Scrapy爬取heima论坛所有页面内容并保存到数据库中

news 2025/7/2 18:15:36

前期准备：

Scrapy入门_win10安装scrapy-CSDN博客

新建 Scrapy项目

scrapy startproject mySpider03 # 项目名为mySpider03

进入到spiders目录

cd mySpider03/mySpider03/spiders

创建爬虫

scrapy genspider heima bbs.itheima.com # 爬虫名为heima ，爬取域为bbs.itheima.com

制作爬虫

items.py:

import scrapyclass heimaItem(scrapy.Item):title = scrapy.Field()url = scrapy.Field()

heima.py:

import scrapy
from scrapy.selector import Selector
from mySpider03.items import heimaItemclass HeimaSpider(scrapy.Spider):name = 'heima'allowed_domains = ['bbs.itheima.com']start_urls = ['http://bbs.itheima.com/forum-425-1.html']def parse(self, response):print('response.url: ', response.url)selector = Selector(response)node_list = selector.xpath("//th[@class='new forumtit'] | //th[@class='common forumtit']")for node in node_list:# 文章标题title = node.xpath('./a[1]/text()')[0].extract()# 文章链接url = node.xpath('./a[1]/@href')[0].extract()# 创建heimaItem类item = heimaItem()item['title'] = titleitem['url'] = urlyield item

pipelines.py:

from itemadapter import ItemAdapter
from pymongo import MongoClientclass heimaPipeline:def open_spider(self, spider):# MongoDB 连接设置  self.MONGO_URI = 'mongodb://localhost:27017/'  self.DB_NAME = 'heima'  # 数据库名称  self.COLLECTION_NAME = 'heimaNews'  # 集合名称self.client = MongoClient(self.MONGO_URI)self.db = self.client[self.DB_NAME]self.collection = self.db[self.COLLECTION_NAME]# 如果集合中已有数据，清空集合self.collection.delete_many({})print('爬取开始')def process_item(self, item, spider):title = item['title']url = item['url']# 将item转换为字典item_dict = {'title': title,'url': url,}# 插入数据self.collection.insert_one(item_dict)return item   def close_spider(self, spider):print('爬取结束，显示数据库中所有元素')cursor = self.collection.find()for document in cursor:print(document)self.client.close()

settings.py，解开ITEM_PIPELINES的注释，并修改其内容:

ITEM_PIPELINES = {

'mySpider03.pipelines.heimaPipeline': 300,

}

创建run.py:

from scrapy import cmdlinecmdline.execute("scrapy crawl heima -s LOG_ENABLED=False".split())# cd mySpider03/mySpider03/spiders

运行run.py文件，即可实现爬取第一页'http://bbs.itheima.com/forum-425-1.html'内容并保存到数据库中的功能。

结果如下图：

爬取到了50条数据。

爬取所有页面

方法一：通过获取下一页url地址的方法爬取所有页面。

在heima.py的parse方法结尾加上以下内容：

# 获取下一页的链接

if '下一页' in response.text:

next_url = selector.xpath("//a[@class='nxt']/@href").extract()[0]

yield scrapy.Request(next_url, callback=self.parse)

即heima.py：

import scrapy
from scrapy.selector import Selector
from mySpider03.items import heimaItemclass HeimaSpider(scrapy.Spider):name = 'heima'allowed_domains = ['bbs.itheima.com']start_urls = ['http://bbs.itheima.com/forum-425-1.html']def parse(self, response):print('response.url: ', response.url)selector = Selector(response)node_list = selector.xpath("//th[@class='new forumtit'] | //th[@class='common forumtit']")for node in node_list:# 文章标题title = node.xpath('./a[1]/text()')[0].extract()# 文章链接url = node.xpath('./a[1]/@href')[0].extract()# 创建heimaItem类item = heimaItem()item['title'] = titleitem['url'] = urlyield item# 获取下一页的链接if '下一页' in response.text:next_url = selector.xpath("//a[@class='nxt']/@href").extract()[0]yield scrapy.Request(next_url, callback=self.parse)

爬取结果：

爬取到了70页，一共3466条数据。

# 在cmd中输入以下命令，查看数据库中的数据：
> mongosh # 启动mongoDB
> show dbs # 查看所有数据库
> use heima # 使用heima数据库
> db.stats() # 查看当前数据库的信息
> db.heimaNews.find() # 查看heimaNews集合中的所有文档

方法二：使用crawlspider提取url链接

新建crawlspider类的爬虫

scrapy genspider -t crawl heimaCrawl bbs.itheima.com

# 爬虫名为heimaCrawl ，爬取域为bbs.itheima.com

2.1在rules中通过xpath提取链接

修改heimaCrawl.py文件：

import scrapy
from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import CrawlSpider, Rule
from mySpider03.items import heimaItemclass HeimacrawlSpider(CrawlSpider):name = 'heimaCrawl'allowed_domains = ['bbs.itheima.com']start_urls = ['http://bbs.itheima.com/forum-425-1.html']rules = (Rule(LinkExtractor(restrict_xpaths=r'//a[@class="nxt"]'), callback='parse_item', follow=True),)# 处理起始页面内容，如果不重写该方法，则只爬取满足rules规则的链接，不会爬取起始页面内容def parse_start_url(self, response):# 调用 parse_item 处理起始页面return self.parse_item(response)def parse_item(self, response):print('CrawlSpider的response.url: ', response.url)node_list = response.xpath("//th[@class='new forumtit'] | //th[@class='common forumtit']")for node in node_list:# 文章标题title = node.xpath('./a[1]/text()')[0].extract()# 文章链接url = node.xpath('./a[1]/@href')[0].extract()# 创建heimaItem类item = heimaItem()item['title'] = titleitem['url'] = urlyield item

修改run.py: