var http = require('http');
http.createServer(function (req, res) {
    res.writeHead(200, {'Content-Type': 'text/plain'});
    res.end('Hello World\n');
}).listen(1337, "127.0.0.1");
console.log('Server running at http://127.0.0.1:1337/');

var replaceTmpl = function(str, conf) {
    return("" + str).replace(/\$(\w+)\$/g, function(a, b) {
        return typeof conf[b] != "undefined" ? conf[b] : "$" + b + "$"
    });
};
var ret = replaceTmpl("pre_$str$_suffix", {str: "HELLO"});
console.log(ret);

• 无处不在的 JavaScript
• 前后端代码的复用！

process.on('uncaughtException', function(err) {
    console.log('got an error: %s', err.message);
    process.exit(1);
});

setTimeout(function() {
    throw new Error('fail');
}, 100);

当同时有好几个请求的时候，Node会通知操作系统(通过 epoll, kqueue, /dev/poll, or select) 如果有新连接来了
吼一声，然后它就睡觉去了。。。只有当新连接来了，操作系统会把它拽醒，它才执行一下回调。于是每个请求对它来说，
就是小菜一碟。而不像其它大多数的 Web Server都会分配一个线程(2MB)去处理。

var http = require('http');
http.createServer(function (req, res) {
    res.writeHead(200, {'Content-Type': 'text/plain'});
    res.end('Hello World\n');
}).listen(1337, "127.0.0.1");
console.log('Server running at http://127.0.0.1:1337/');

• 单线程
• no lock at all...
• so never dead locking...

/usr/sbin/ab -n 10000 -c 10 http://localhost:8080/

/usr/sbin/ab -n 100000 -c 1000 http://localhost:8080/

支持各种常用的存储系统

• mysql
• memcache
• mongodb
• redis

以最常用的 mysql 为例子，https://github.com/felixge/node-mysql

var mysql      = require('mysql');
var connection = mysql.createConnection({
  host     : 'localhost',
  user     : 'me',
  password : 'secret',
});
connection.connect();
connection.query('SELECT 1 + 1 AS solution', function(err, rows, fields) {
  if (err) throw err;
  console.log('The solution is: ', rows[0].solution);
});
connection.end();

类似于 Java 的 Connection Pool，nodejs也有 Connection Pool

• mysql
• memcache
• mongodb
• redis

以最常用的 mysql 为例子

var mysql = require('mysql');
var pool  = mysql.createPool({
  host     : 'example.org',
  user     : 'bob',
  password : 'secret'
});
pool.getConnection(function(err, connection) {
  // Use the connection
  connection.query( 'SELECT something FROM sometable', function(err, rows) {
    // And done with the connection.
    connection.end();
    // Don't use the connection here, it has been returned to the pool.
  });
});

• Real Long Connection
• 兼容所有浏览器
• 100% javascript，前后端长一个样。。。

var io = require('socket.io').listen(9090);

io.sockets.on('connection', function (socket) {
  socket.emit('news', { hello: 'world' });
  socket.on('my other event', function (data) {
    console.log(data);
  });
});

<script src="/socket.io/socket.io.js"></script>
<script>
  var socket = io.connect('http://localhost');
  socket.on('news', function (data) {
    console.log(data);
    socket.emit('my other event', { my: 'data' });
  });
</script>

• JavaScript Tast Runner
• 各种自动化，压缩，打包，单元测试，语法检查，部署，等等