json yeid_请问一下， scrapy 在一个 def 里不能发多个 yield Request 请求么？为什么？...

这是我写的 spider 文件，下面有我碰到的在一个页面内所需要的值，放在 3 个 json 文件中。。。。。所以我在一个函数下写了三个 yield Request 请求……

import scrapy

from scrapy.http import Request

import re

from jingdong.items import JingdongItem

from jingdong.settings import *

class GoodsSpider(scrapy.Spider):

name = 'goods'

allowed_domains = ['jd.com']

start_urls = ['http://jd.com/']

# https://search.jd.com/Search?keyword=图书&enc=utf-8&wq=图书&page=1

# 搜索的起始页

url = "https://search.jd.com/Search?keyword={KEYWORDS}&enc=utf-8&wq={KEYWORDS}&page={page}"

# 电子价格

Eprice_url = "https://c.3.cn/book?skuId={skuId}&cat={cat}&area=1_72_2799_0&callback=book_jsonp_callback"

# 商品价格

price_url = "https://p.3.cn/prices/mgets?type=1&area=1_72_2799_0&pdtk=&pduid=1771569446&pdpin=&pdbp=0&skuIds=J_{skuId}&ext=11100000&callback=jQuery3021180&_=1547383556702"

price2_url = 'https://c0.3.cn/stock?skuId={skuId}&venderId=1000005720&cat={cat}&area=1_72_2799_0&buyNum=1&extraParam={%22originid%22:%221%22}&ch=1&pduid=1771569446&pdpin=&fqsp=0&callback=getStockCallback'

# 评论

comment_url = "https://sclub.jd.com/comment/productPageComments.action?callback=fetchJSON_comment98vv39228&productId={skuId}&score=0&sortType=5&page=0&pageSize=10&isShadowSku=0&fold=1"

def start_requests(self):

for k in range(1,PAGE_NUM):

yield Request(url=self.url.format(KEYWORDS=KEYWORDS,page=2*k-1),callback=self.page_parse)

def page_parse(self, response):

#每页商品 ID

goodsID = response.xpath('//li/@data-sku').extract()

print(goodsID)

for each in goodsID:

goodsurl = "https://item.jd.com/{}.html".format(each)

yield Request(url=goodsurl,callback=self.get_goods_info)

def get_goods_info(self,response):

item = JingdongItem()

#图书链接

item["link"] = response.url

#图书标题

item["title"] = response.xpath('//div[@class="sku-name"]/text()').extract()[0].strip()

#作者

item["writer"] = response.xpath('//div[@class="p-author"]/a/text()').extract()

#提取商品 ID

skuId = re.compile(r'https:..item.jd.com.(\d+).html').findall(response.url)[0]

item['Id'] = skuId

cat = re.compile(r'pcat:\[(.*?)\],').findall(response.text)

cat = re.sub("\|",",",cat[0]).strip("'")

item['catId'] = cat

print(skuId)

print(cat)

# 打开电子书价格

yield Request(url = self.Eprice_url.format(skuId=skuId, cat=cat),meta={'item':item},callback=self.price_parse)

# 打开原价及京东价

yield Request(url = self.price_url.format(skuId=skuId),meta={'item':item},callback=self.jingdong_price_parse)

# 打开评论 json

yield Request(url = self.comment_url.format(skuId=skuId),meta={'item':item},callback=self.comment_parse)

def price_parse(self,response):

item =response.meta['item']

#电子书价格

item["e_price"] = re.compile('"p":"(.*?)",').findall(response.text)[0]

yield item

def jingdong_price_parse(self,response):

item = response.meta['item']

#京东价

item["n_price"] = re.compile('"op":"(.*?)",').findall(response.text)[0]

print(item["n_price"])

#原价

item["o_price"] = re.compile('"m":"(.*?)",').findall(response.text)[0]

if item["n_price"] == None and item["o_price"]== None:

yield Request(url=self.price2_url.format(skuId=item['id'],cat=item['catId']),meta={'item':item}, callback=self.jingdong_price_parse)

else:

yield item

def comment_parse(self,response):

item = response.meta['item']

#评论数

item["comment"] =re.compile('"content":"(.*?)",').findall(response.text)

yield item

如题目说所，这三个请求

# 打开电子书价格

yield Request(url = self.Eprice_url.format(skuId=skuId, cat=cat),meta={'item':item},callback=self.price_parse)

# 打开原价及京东价

yield Request(url = self.price_url.format(skuId=skuId),meta={'item':item},callback=self.jingdong_price_parse)

# 打开评论 json

yield Request(url = self.comment_url.format(skuId=skuId),meta={'item':item},callback=self.comment_parse)

将会只执行最下面的，另外两个获取不到值。我试过单独写一个爬虫来同相同的匹配规则是可以正常获取到的。所以，百思不得其解啊！！！！！