flask框架为什么不能执行类

from flask import Flask,Blueprint
app = Flask(__name__)

import requests
import time
from lxml import etree
import random


@app.route('/')
class Spider:
    def __init__(self):
        self.index_url="https://www.daomubiji.com/"

    def get_html(self,url):
        """功能函数一: 请求获取html"""
        headers={'user-agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.93 Safari/537.36'}
        html=requests.get(url=url,headers=headers,verify=False).text
        return html

    def xfunc(self,html,x):
        """功能函数2: 解析html请求"""
        eobj=etree.HTML(html)
        r_list=eobj.xpath(x)

        return r_list

    def parse_html(self):
        """爬虫逻辑函数"""
        first_html=self.get_html(url=self.index_url)
        first_x='//li[contains(@id,"menu-item-20")]'
        li_list=self.xfunc(first_html,first_x)
        for li in li_list:
            """提取大标题和大链接"""
            item1={}
            item1["parent_title"]=li.xpath('./a/text()')[0]
            item1["parent_href"]=li.xpath('./a/@href')[0]
            # 解析提取二级页面数据
            self.parse_two_html(item1)

    def parse_two_html(self,item1):
        """二级页面解析:小标题和小链接"""
        two_url=item1["parent_href"]
        two_html=self.get_html(two_url)
        two_x='//article'
        art_list=self.xfunc(two_html,two_x)
        # print(art_list)
        for art in art_list:
            item2={}
            item2['parent_title']=item1["parent_title"]
            item2['parent_href']=item1["parent_href"]
            item2["son_title"]=art.xpath('./a/text()')[0]
            item2["son_href"]=art.xpath('./a/@href')[0]
            # 解析提取三级页面数据
            self.parse_three_html(item2)
            # 控制频率
            time.sleep(random.uniform(0,1))

    def parse_three_html(self,item2):
        """三级页面解析:小说内容"""
        three_url = item2["son_href"]
        three_html = self.get_html(three_url)
        three_x = '//article/p/text()'
        p_list = self.xfunc(three_html, three_x)
        novel_content='\n'.join(p_list)
        item2['novel_content']=novel_content.replace('\u3000',' ')
        item_list = [item2['parent_title'], item2['parent_href'], item2['son_title'], item2['son_href'], item2['novel_content']]
        # print(item_list)
        return item_list

    def carw(self):
        self.parse_html()
if __name__ == '__main__':
    spider=Spider()
    spider.carw()



if __name__ == '__main__':
    app.run()

中间的类是我写的爬虫程序，为什么不能在flask里执行

调整下顺序试试

# import 代码 。。。

# class 定义  。。。。

app = Flask(__name__)

@app.route('/')
def test():
    spider=Spider()
    spider.carw()
 
 
 
if __name__ == '__main__':
    app.run()