//express app mysqlvar express = require('express');var app = express();var bodyParser = require('body-parser');var mysql = require('mysql');//连接数据库var connection = mysql.createConnection({  host: 'localhost',  user: 'root',  password: 'lyx117',  database: 'test'})connection.connect();//查var sql = 'SELECT * FROM tb1';//增var sql1 = 'INSERT INTO tb1 (id,name,age) VALUES (6,"TE",15)';//删var sql2 = 'DELETE FROM tb1 WHERE age=15'//查到tb1所有数据并返回connection.query(sql, function (err, result) {  if (err) {    throw err;    return;  }  var tb = JSON.parse(JSON.stringify(result))  // 创建 application/x-www-form-urlencoded 编码解析    var urlencodedParser = bodyParser.urlencoded({ extended: false })  // create application/json parser  var jsonParser = bodyParser.json()  app.get('/', function (req, res) {    res.send(tb);  });  app.get('/tb', function (req, res) {    res.setHeader("Access-Control-Allow-Origin", "*");    res.send(tb);  });  app.post('/login', urlencodedParser, function (req, res) {    if (!req.body) return res.sendStatus(400)    res.send('welcome, ' + req.body.username)  })  app.post('/api/users', jsonParser, function (req, res) {    if (!req.body) return res.sendStatus(400)    // create user in req.body  })})connection.end;var server = app.listen(8081, function () {  var host = server.address().address;  var port = server.address().port;  console.log("address: %s, port: %d", host, port);});

　　另外,全局安装热部署工具 npm install -g supervisor  

　　使用supervisor代替nodejs启动应用

 　　这样每次修改就不用手动开启了

　　但是supervisor 启动会占用很大的内存，可以全局安装 hotnode