// filename:myServer.js
// a simple http server
var
 fs = require('fs'),
 url = require('url'),
 path = require('path'),
 http = require('http');

//从命令行参数获取root目录，默认是当前目录
var root = path.resolve(process.argv[2] || '.');
console.log('Static root dir: ' + root);

//创建服务器
var server = http.createServer(function (request, response) {
 //获取URL的路径
 var pathname = url.parse(request.url).pathname,
 //获取对应的本地文件的路径
 filepath = path.join(root, pathname);
 //获取文件状态
 fs.stat(filepath, function (err, stats) {
 if (!err && stats.isFile()) {
  console.log('200 ' + request.url);
  //发送响应
  response.writeHead(200);
  //将文件流导向response
  fs.createReadStream(filepath).pipe(response);
 } else {
  console.log('404 ' + request.url);
  response.writeHead(404);
  response.end('404 Not Found');
 }
 });
});

server.listen(8081);
console.log('Server is running at http://127.0.0.1:8081/');