nodejs中创建web服务被忽略的坑---listen hostname

nodejs中创建web服务时，习惯看官网例子

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/');

官网的API上说到：

server.listen(port, [hostname], [backlog], [callback])#

Begin accepting connections on the specified port and hostname. If the hostname is omitted, the server will accept connections directed to any IPv4 address (INADDR_ANY).

里面说到如果忽略了hostname，那么服务器将会接受所有IPV4地址的链接，IPv4地址包括127.0.0.1 localhost和本地IP。没有认真看API，以后要注意。那么这样做就可以实现监听本地IP、localhost、127.0.0.1了：

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