express是Node.js的官方唯一推荐的框架，它扩展了http工具以及一些好用的功能。如此好用的东西，赶紧的安装起来：

npm install express -g

新版本的express的命令集中到了另一个插件中，简单的如同以前一样的express
-V运行的返回不是它的版本号，而是提示“express不是内部或外部命令”了，所以还要安装express-generator，同样：

npm install express-generator -g

好了，版本检查如下：

$ express -V

//4.2.0

安装好了，首先来看看如何建立一个项目：

cd e:\...\root

express myproject

命令窗口提示：

create : myproject

create : myproject/package.json

create : myproject/app.js

create : myproject/public

create : myproject/public/javascripts

create : myproject/public/images

create : myproject/routes

create : myproject/routes/index.js

create : myproject/routes/users.js

create : myproject/public/stylesheets

create : myproject/public/stylesheets/style.css

create : myproject/views

create : myproject/views/index.jade

create : myproject/views/layout.jade

create : myproject/views/error.jade

create : myproject/bin

create : myproject/bin/www

install dependencies:

  $ cd myproject && npm install

run the app:

  $ DEBUG=myproject ./bin/www

窗口提示信息如上所示，根据提示，进入myproject目录，

cd myproject && npm install

这里的install是安装项目需要依赖的包，运行后的提示：

debug@0.7.4 node_modules\debug

static-favicon@1.0.2 node_modules\static-favicon

morgan@1.0.1 node_modules\morgan

└── bytes@0.3.0

cookie-parser@1.0.1 node_modules\cookie-parser

├── cookie-signature@1.0.3

└── cookie@0.1.0

body-parser@1.0.2 node_modules\body-parser

├── qs@0.6.6

├── type-is@1.1.0 (mime@1.2.11)

└── raw-body@1.1.7 (string_decoder@0.10.25-1, bytes@1.0.0)

express@4.2.0 node_modules\express

├── parseurl@1.0.1

├── qs@0.6.6

├── merge-descriptors@0.0.2

├── cookie-signature@1.0.3

├── debug@0.8.1

├── escape-html@1.0.1

├── methods@1.0.0

├── buffer-crc32@0.2.1

├── cookie@0.1.2

├── serve-static@1.1.0

├── fresh@0.2.2

├── utils-merge@1.0.0

├── range-parser@1.0.0

├── path-to-regexp@0.1.2

├── type-is@1.1.0 (mime@1.2.11)

├── send@0.3.0 (debug@0.8.0, mime@1.2.11)

└── accepts@1.0.1 (mime@1.2.11, negotiator@0.4.7)

jade@1.3.1 node_modules\jade

├── commander@2.1.0

├── character-parser@1.2.0

├── mkdirp@0.3.5

├── transformers@2.1.0 (promise@2.0.0, css@1.0.8, uglify-js@2.2.5)

├── monocle@1.1.51 (readdirp@0.2.5)

├── constantinople@2.0.1 (uglify-js@2.4.15)

└── with@3.0.0 (uglify-js@2.4.15)

此时项目的node_modules中的目录如图，即为上述的安装提示信息中的那些包。

回到根目录/myproject下，找到package.json文件，可以看到，刚刚安装的这些包等等的信息都已经配置到该文件中去了

var express = require('express');

var path = require('path');

var favicon = require('static-favicon');

var logger = require('morgan');

var cookieParser = require('cookie-parser');

var bodyParser = require('body-parser');

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

var users = require('./routes/users');

var app = express();

app.set('views', path.join(__dirname, 'views'));

app.set('view engine', 'jade');

app.use(favicon())；

app.use(logger('dev'));

app.use(bodyParser.json());

app.use(bodyParser.urlencoded());

app.use(cookieParser());

app.use(express.static(path.join(__dirname, 'public')));

app.use('/', routes);

app.use('/users', users);

app.use(function(req, res, next) {

    var err = new Error('Not Found');

    err.status = 404;

    next(err);

});

if (app.get('env') === 'development') {

    app.use(function(err, req, res, next) {

        res.status(err.status || 500);

        res.render('error', {

            message: err.message,

            error: err

        });

    });

}

app.use(function(err, req, res, next) {

    res.status(err.status || 500);

    res.render('error', {

        message: err.message,

        error: {}

    });

});

module.exports = app;

var express = require('express');

var router = express.Router();

router.get('/',function(req,res){

    res.send('<h1>Hello world!</h1>');

});

module.exports = router;

var hello = require('./routes/hello');

app.use('/hello', hello);