基础使用

创建服务

const express = require('express')
const app = express()
const port = '7890'

app.get('/', (req, res) => {
  res.send('hello node.js')
})

const server = app.listen(port, () => {
  const host = server.address().address
  const port = server.address().port
  console.log('Now we are service at http://%s:%s', host, port)
})