node -v

node

var num1 = 10;
var num2 = 20;
console.log(num1 + num2);

{
 "name": "Node_Hello",
 "description": "nodejs hello world app",
 "version": "0.0.1",
 "private": true,
 "dependencies": {
  "express": "4.x"
 }
}

npm install

var express = require('express');
var app = express();
app.get('/', function (req, res) {
 res.send('<h1>你好，這是我們的第一個nodejs項目</h1>');
});
app.listen(8080);

//加載模塊
var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
//加載路由文件
var index = require('./routes/index');
var users = require('./routes/users');

// 生產(chǎn)一個express的實例
var app = express();

// view engine setup
/*
設置 views 文件夾為存放視圖文件的目錄,
即存放模板文件的地方,__dirname 為全局變量,
存儲當前正在執(zhí)行的腳本所在的目錄。
 */
app.set('views', path.join(__dirname, 'views'));
//設置模板引擎為ejs
app.set('view engine', 'ejs');

// uncomment after placing your favicon in /public
//app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));
//加載日志中間件
app.use(logger('dev'));
//加載解析json的中間件
app.use(bodyParser.json());
//加載解析urlencoded請求體的中間件。 post請求
app.use(bodyParser.urlencoded({extended: false}));
//加載解析cookie的中間件
app.use(cookieParser());
//設置public文件夾為放置靜態(tài)文件的目錄
app.use(express.static(path.join(__dirname, 'public')));

// 路由控制器。
app.use('/', index); // http://localhost:3000
app.use('/users', users);  //http://localhost:3000/users


// catch 404 and forward to error handler
app.use(function (req, res, next) {
  var err = new Error('Not Found');
  err.status = 404;
  next(err);
});

// error handler
app.use(function (err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.render('error');
});

//把app導出。 別的地方就可以通過 require("app") 獲取到這個對象
module.exports = app;

#!/usr/bin/env node //表明是node可執(zhí)行文件

/**
 * Module dependencies.
 */
//引入我們在app.js中導出的app模塊
var app = require('../app');
//引入debuger模塊，打印調(diào)試日志
var debug = require('debug')('hello:server');
//引入http模塊
var http = require('http');

/**
 * Get port from environment and store in Express.
 */

var port = normalizePort(process.env.PORT || '3000');
app.set('port', port); //設置端口號

/**
 * Create HTTP server.
 */
//創(chuàng)建Http服務器
var server = http.createServer(app);

/**
 * Listen on provided port, on all network interfaces.
 */
//監(jiān)聽指定的端口
server.listen(port);
//監(jiān)聽error事件。 onError是發(fā)生錯誤的時候的回調(diào)函數(shù)
server.on('error', onError);
//監(jiān)聽listening事件
server.on('listening', onListening);

/**
 * Normalize a port into a number, string, or false.
 */

function normalizePort(val) {
 var port = parseInt(val, 10);

 if (isNaN(port)) {
  // named pipe
  return val;
 }

 if (port >= 0) {
  // port number
  return port;
 }

 return false;
}

/**
 * Event listener for HTTP server "error" event.
 */

function onError(error) {
 if (error.syscall !== 'listen') {
  throw error;
 }

 var bind = typeof port === 'string'
  ? 'Pipe ' + port
  : 'Port ' + port;

 // handle specific listen errors with friendly messages
 switch (error.code) {
  case 'EACCES':
   console.error(bind + ' requires elevated privileges');
   process.exit(1);
   break;
  case 'EADDRINUSE':
   console.error(bind + ' is already in use');
   process.exit(1);
   break;
  default:
   throw error;
 }
}
/**
 * Event listener for HTTP server "listening" event.
 */

function onListening() {
 var addr = server.address();
 var bind = typeof addr === 'string'
  ? 'pipe ' + addr
  : 'port ' + addr.port;
 debug('Listening on ' + bind);
}

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

/* GET home page. */
router.get('/', function(req, res, next) {
 res.render('index', { title: '育知同創(chuàng)' });
});

module.exports = router;
/*
 生成一個路由實例用來捕獲訪問主頁的GET請求，
 導出這個路由并在app.js中通過app.use('/', routes);
 加載。這樣，當訪問主頁時，就會調(diào)用res.render('index', { title: '育知同創(chuàng)' });
 渲染views/index.ejs模版并顯示到瀏覽器中。
 */

//加載路由文件
var index = require('./routes/index'); //去掉
var users = require('./routes/users'); //去掉
// 路由控制器。
app.use('/', index); // http://localhost:3000 //去掉
app.use('/users', users);  //http://localhost:3000/users  //去掉

var routes = require('./routes/index');
routes(app);

module.exports = function (app) {
 //一個get請求的路由 http://localhost:3000
 app.get("/", function (req, res) {
   res.render("index", {title:"育知同創(chuàng)abc"})
 });
 //又一個請求路由：http://localhost:3000/abc
 app.get("/abc", function (req, res) {
   res.render("index", {title:"育知同創(chuàng)" + req.path})
 });
}

app.set('views', __dirname + '/views');
app.set('view engine', 'ejs');

<!DOCTYPE html>
<html>
 <head>
  <title><%= title %></title>
  <link rel='stylesheet' href='/stylesheets/style.css' />
 </head>
 <body>
  <h1><%= title %></h1>
  <p>Welcome to <%- title %></p>
 </body>
</html>

router.get('/', function(req, res, next) {
 res.render('index', { title: "<a >百度 </a>"});
});

// 則會用title的值去替換ejs中的相應的代碼。

<!DOCTYPE html>
<html>
 <head>
  <title>&lt;a href=&#39;http://www.baidu.com&#39;&gt;百度 &lt;/a&gt;</title>
  <link rel='stylesheet' href='/stylesheets/style.css' />
 </head>
 <body>
  <h1>&lt;a href=&#39;http://www.baidu.com&#39;&gt;百度 &lt;/a&gt;</h1>
  <p>Welcome to <a >百度 </a></p>
 </body>
</html>