~~~ const koa = require('koa'); const router = require('koa-router')(); const app = new koa(); app.use(async (ctx,next)=>{ console.log(new Date()) next() if(ctx.status == 404){ ctx.status =404; ctx.body="这是一个404页面" } }) app.use(async (ctx,next)=>{ console.log("这是一个中间件") next() } ) router.get('/',async ctx=>{ console.log("index") ctx.body="index" }) router.get('/detail',async ctx=>{ console.log('detail') ctx.body = "detail" }) app.use(router.routes()).use(router.allowedMethods()) app.listen(8080) ~~~