app.js

const express=require('express')
let router=require('./router')
const bodyParser = require('body-parser')
const path = require('path')
const app=express()

//公开资源
app.use(express.static('public'))
app.use(express.static('node_modules'))

//模板引擎
app.engine('html',require('express-art-template'))

// parse application/x-www-form-urlencoded
app.use(bodyParser.urlencoded({ extended: false }))
// parse application/json
app.use(bodyParser.json())

//把路由容器挂载到app服务中
app.use(router)

app.use(function (req,res,next) {
    res.send('404')
})

//配置错误处理中间件
app.use(function (err,req,res,next) {
    res.status(500).json({
        err_code:500,
        message:err.message
    })
})

app.listen(3000,function () {
    console.log('app is running!')
})