node.js require(“mongodb”)抛出一个exception

我是node.js的新手(但有10年的C#经验)我有以下代码

 var http = require("http"); var url = require("url"); var path = require('path'); var fs = require("fs"); var express = require("express"); var mongo = require("./node_modules/mongo"); var Server = mongo.Server; var Db = mongo.Db; var server = new Server('localhost', 27017, {auto_reconnect: true}); var db = new Db('mydb', server); 

我得到这个例外:

错误:找不到模块'./node_modules/mongo'

 at Function.Module._resolveFilename (module.js:338:15) 

我也试过:

 var mongo = require("mongo"); 

试试这个:

 var mongodb = require('mongodb');