express路由，mongoose，koa-router写法模

app里面引入两个路由文件，并声明使用

var categoryRouter = require('./routes/category.js');
var userRouter = require('./routes/user.js');

app.use('/api/category', categoryRouter);
app.use('/api/user', userRouter);

express路由写法
定义两个路由文件
第一个category.js

var express = require('express');
var router = express.Router();

router.get('/', function(req, res, next) {
  res.send("this is category root")
});

router.get('/list', function(req, res, next) {
  res.send("this is list")
});

router.get('/add', function(req, res, next) {
  res.send("this is add")
});

module.exports = router;

第二个user.js

var express = require('express');
var router = express.Router();

router.get('/', function(req, res, next) {
  res.send("this is user root")
});

router.get('/reg', function(req, res, next) {
  res.send("this is user reg")
});

module.exports = router;

下面是数据库模型的引入写法
首先创建一个db.js文件，引入mongoose，写模型，然后导出

var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/epresstoken');

var userSchema = new mongoose.Schema({
    name: String,
    age: Number
})      
var userModel = mongoose.model('userModel', userSchema, 'user');


var articalSchema=new mongoose.Schema({
    title:String,
    author:String
})
var articalModel=mongoose.model("articalModel",articalSchema,"artical");

module.exports={userModel,articalModel}

接着，在路由文件里引入模型，用来使用

var express = require('express');
var router = express.Router();

var {userModel} = require("../db.js");
//引入模型

router.get('/reg', function(req, res, next) {
  let temp=new userModel({name:"zyw",age:32});
  temp.save()
});

module.exports = router;

koa写法
首先app里面这样写，注意顺序
const Koa = require("koa");
const app=new Koa();

const cors = require('koa2-cors');
app.use(cors());

const bodyParser = require('koa-bodyparser');
app.use(bodyParser());

const reg = require('./routes/reg.js')
app.use(reg.routes(), reg.allowedMethods())

app.listen(3000)
然后写路由，在./routes/下面新建一个reg.js
const router = require('koa-router')();

router.post('/reg', async (ctx, next)=> {
    ctx.body = ctx.request.body;
})

module.exports = router
这样一个koa路由api就搭建好了