用 node 的 express 插件创建应用

mkdir myapp
cd myapp
npm install express --save
vim app.js

//app.js 内容

var express = require("express");
var app = express();

app.get("/", function (req, res) {
  res.send("Hello World!");
});

var server = app.listen(3000, function () {
  var host = server.address().address;
  var port = server.address().port;
  console.log("Example app listening at http://%s:%s", host, port);
});

node app.js