nodejs，koa2本地接口，ajax請(qǐng)求偶爾報(bào)404,是什么問(wèn)題？server.jsconst Koa =require('koa');const app=new Koa();const mongoose=require('mongoose');const bodyParser = require('koa-bodyparser');const cors = require('koa2-cors');const router = require('./router/router')();//義務(wù)const database='mongodb://localhost:27018/koa2';//本地?cái)?shù)據(jù)庫(kù)地址app.use(bodyParser());//處理post請(qǐng)求app.use(cors());//處理跨域app    .use(router.routes())    .use(router.allowedMethods());mongoose.connect(database, function (err) {    if (err) {        console.log('數(shù)據(jù)庫(kù)連接失敗');    } else {        app.listen(9000);        console.log('端口9000，數(shù)據(jù)庫(kù)連接成功');    }});