```javascript const Koa = require('koa'); const logger = require('koa-logger'); const Router = require('koa-router'); const cors = require('@koa/cors'); const compose = require('koa-compose') const qs = require('qs'); //解析querystring const app = new Koa(); app.use(logger());//記錄日志 app.use(cors());//支持跨域請求 // 主頁（非RESTful格式的API） let routerHome = new Router(); routerHome.get('/', async (ctx, next) => { ctx.body = '歡迎歡迎！'; }) // RESTful API let routerRest = new Router(); //獲取指定資源resource的列表 //例如：http://localhost:3000/resource routerRest.get('/resource', async (ctx, next) => { ctx.body = { errno: 0, errmsg: 'GET API執行成功', data: '返回的數據' //這里放回一個數據列表 }; }) //獲取指定ID的資源 //例如：http://localhost:3000/resource/1?name=zengqs&age=18 routerRest.get('/resource/:id', async (ctx, next) => { //參數解析示例 console.log(ctx.params); //{ id: '1' } console.log(ctx.querystring);//name=zengqs&age=18 let obj = qs.parse(ctx.querystring); console.log(obj) //{ name: 'zengqs', age: '18' } let id = ctx.params.id; ctx.body = { errno: 0, errmsg: 'GET API執行成功', data: '返回的數據' //檢索數據庫，返回指定id的數據 }; }) //新增記錄，數據通過BODY傳遞 routerRest.post('/resource', async (ctx, next) => { ctx.body = { errno: 0, errmsg: 'POST API執行成功', data: '返回的數據' }; }) //刪除指定ID的數據 routerRest.delete('/resource/:id', async (ctx, next) => { let id = ctx.params.id; ctx.body = { errno: 0, errmsg: 'POST API執行成功', data: '返回的數據' }; }) //更新指定ID的數據，數據通過BODY傳遞 routerRest.put('/resource/:id', async (ctx, next) => { let id = ctx.params.id; ctx.body = { errno: 0, errmsg: 'POST API執行成功', data: '返回的數據' }; }) app.use(compose([routerHome.routes(), routerHome.allowedMethods()])) app.use(compose([routerRest.routes(), routerRest.allowedMethods()])) //監聽3000端口 app.listen(3000, () => { console.log('server is running at http://localhost:3000') }); ```