nodejs中创建web服务，监听本地IP

nodejs官网例子

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

写web service时，都是习惯监听的hostname为127.0.0.1，那么我要监听localhost和本地IP怎么办？一下子糊涂了。后面找到官网的API

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).

里面有说到忽略hostname就会接受IPv4地址了，那么在程序中不要写hostname，即listen(1337)就可以了，可以监听127.0.0.1 localhost 和本地IP了。