爬虫框架scrapy（1）持久化存储的多种方式及多页爬取数据

Linux：pip3 install scrapy

window:

　　a:pip3 install wheel

　　b:下载twisted高性能异步模块 https://www.lfd.uci.edu/~gohlke/pythonlibs/#twisted 

　　c:进入下载的目录 执行pip3 install Twisted-17.1---.whl

　　d:pip3 install pywin32

　　e:pip3 install scrapy

　　f:pip3 install scrapy

创建项目：scrapy startproject 项目名称

创建爬虫文件：cd 项目 

　　　　　　　scrapy genspider 爬虫文件名 www.baidu.com

启动爬虫文件：scray crawl 爬虫文件 --nolog

框架简单理解：spiders文件下存放爬虫文件

　　　　　　　items文件存放永久化存储的属性字段，与管道配合使用

　　　　　　　middlewares中间件存放下载中间件与爬虫中间件

　　　　　　　管道做持久化存储，可以写多个管道文件

　　　　　　　settings文件做配置

setting文件配置：

　　添加User-Agent：USER_AGENT = 'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36'

　　ROBOT.TXT改为false：ROBOTSTXT_OBEY = False

　　如需持久化存储将管道文件注释打开，如有多个管道文件，要条件注册，并写好优先级

　　如需中间件操作需要将中间件注释打开

案例1 直聘网获取岗位信息 核心：多种持久化存储方式的管道配置

class BoosSpider(scrapy.Spider):
    name = 'boos'
    # allowed_domains = ['www.baidu.com']
    start_urls = [
        'https://www.zhipin.com/job_detail/?query=python%E7%88%AC%E8%99%AB&scity=101010100&industry=&position=']

    def parse(self, response):
        li_list = response.xpath('//div[@class="job-list"]/ul/li')
        for li in li_list:
            title = li.xpath('.//div[@class="info-primary"]/h3/a/div[@class="job-title"]/text()').extract_first()
            price = li.xpath('.//div[@class="info-primary"]/h3/a/span/text()').extract_first()
            company = li.xpath('.//div[@class="info-company"]/div/h3/a/text()').extract_first()

            item = BoosproItem()
            item['title']=title
            item['price']=price
            item['company'] = company
            yield item　　

　　item配置

class BoosproItem(scrapy.Item):
    # define the fields for your item here like:
    # name = scrapy.Field()
    title = scrapy.Field()
    price = scrapy.Field()
    company = scrapy.Field()

　　管道配置

import pymysql
from redis import Redis
import json
class BoosproPipeline(object):
    fp = None
    def open_spider(self,spider):
        print("开始爬虫")
        self.fp = open('./job.txt','w',encoding='utf-8')
    def process_item(self, item, spider):
        self.fp.write(item['title']+'	'+item['price']+'	'+item['company']+'
')
        return item
    def close_spider(self,spider):
        print('爬虫结束!!!')
        self.fp.close()


class MysqlPipeline(object):
    conn =None
    cursor =None
    def open_spider(self,spider):
        print("开始爬虫")
        self.conn = pymysql.Connect(host='127.0.0.1', port=3306, user='root', password='321', db='pa')
    def process_item(self, item, spider):
        self.cursor = self.conn.cursor()
        sql='insert into job values ("%s","%s","%s")'%(item['title'],item['price'],item['company'])
        try:
            self.cursor.execute(sql)
            self.conn.commit()
        except Exception as e:
            print(e)
            self.conn.rollback()
        return item
    def close_spider(self,spider):
        print('爬虫结束!!!')
        self.cursor.close()
        self.conn.close()


class ReidsPipeline(object):
    conn =None
    def open_spider(self,spider):
        print("开始爬虫")
        self.conn = Redis(host='127.0.0.1', port=6379 ,db=14)
    def process_item(self, item, spider):
        dic = {
            'title':item["title"],
            'price':item['price'],
            'company':item['company']
        }
        dic= json.dumps(dic,ensure_ascii=False)
        self.conn.lpush('jobinfo',dic)
        return item

案例2 多页爬去网站信息

爬虫文件

import scrapy
from chouti.items import ChoutiItem

class CtSpider(scrapy.Spider):
    name = 'ct'
    # allowed_domains = ['www.baidu.com']
    url = 'https://dig.chouti.com/r/scoff/hot/%d'
    page_num =1
    start_urls = ['https://dig.chouti.com/r/scoff/hot/1']

    def parse(self, response):
        div_list = response.xpath('//div[@id="content-list"]/div')
        for div in div_list:
            head = div.xpath('./div[3]/div[1]/a/text()').extract_first()
            author = div.xpath('./div[3]/div[2]/a[4]/b/text()').extract_first()

            item = ChoutiItem()
            item['head'] = head
            item['author'] = author

            yield item

        if self.page_num<5:
            self.page_num+=1
            new_url = format(self.url%self.page_num)
            yield scrapy.Request(url=new_url, callback=self.parse)

items配置

import scrapy


class ChoutiItem(scrapy.Item):
    # define the fields for your item here like:
    # name = scrapy.Field()
    head = scrapy.Field()
    author = scrapy.Field()
    pass

管道配置

class ChoutiproPipeline(object):
    def process_item(self, item, spider):
        print(item['head'],item['author'])
        return item