url_rl = "https://www.yijiupi.com/v31/Product/ListProduct"
payload = '{"currentPage":1,"data":{"sonCategoryId":"%s","categoryIds":["%s"],"saleModel":-1,"sort":0,"currentPage":1,"pageSize":60},"pageSize":60,"addressId":1745761,"deviceType":3}'%(cat_id,cat_id)
# return [scrapy.Request(url=url_rl, body=json.dumps(payload), method="POST", callback=self.get_page_num)]
#这里的payload之前是字典类型，所以要换成字符串类型json.dumps(payload)，但是之后的payload就是字符串类型了，所以直接写payload就行
request = scrapy.Request(url=url_rl, body=payload, method="POST", callback=self.get_page_sum)
#return [scrapy.Request(url=url_rl, body=json.dumps(payload), method="POST", callback=self.get_page_num)]
yield request
这里的payload之前是字典类型，用return发送请求是需要字符串类型，所以要换成字符串类型json.dumps(payload)，在用yield发送请求是需要的是字典类型，所以直接写payload就行，上面的是yield发送请求，所以body直接等于payload就可以了。
data_url = eval('{"orderby": "0","productTypeId": "%s","currentPage": "%s","pageSize": "12"}' %(id,i))
request = scrapy.FormRequest(url=url, formdata=data_url, callback=self.get_parse,dont_filter=True)
