将Express与Node.js结合使用时出现错误 [英] Getting error while using Express with Node.js

问题描述

我用npm express编写了一个小程序.当我运行程序时，出现如下错误.(我是node.js的新手)

I wrote a small program using npm express. while I am running the program i am getting error like below.(I am new to node.js)

module.js:340
    throw err;
          ^
Error: Cannot find module 'express'
    at Function.Module._resolveFilename (module.js:338:15)
    at Function.Module._load (module.js:280:25)
    at Module.require (module.js:362:17)
    at require (module.js:378:17)
    at Object.<anonymous> (C:\Users\node\node_modules\app.js:1:77)
    at Module._compile (module.js:449:26)
    at Object.Module._extensions..js (module.js:467:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Module.runMain (module.js:492:10)

推荐答案

在您的应用程序内部，您显然需要 express 模块，可能是这样的:

Inside your app you obviously require the express module, probably like this:

var express = require('express');

要使此行正常工作，您需要将Express安装到应用程序的本地上下文中.为此，请运行

For this line to work you need to install Express into the local context of your application. To do so run

$ npm install express

在您应用程序的文件夹内.这将(如果尚不存在)创建一个文件夹 node_modules ，您的所有依赖项都将存放在该文件夹中.

inside your application's folder. This will (if it does not yet exist) create a folder node_modules where all your dependencies go.

此外，我建议您将Express放入 dependencies 块内的 package.json 中，例如:

Additionally, I'd suggest that you put Express into your package.json inside the dependencies block, such as:

"dependencies": {
  "express": "3.1.0"
}

当然，您可以将版本号调整为所使用的任何版本.对所有依赖项完成此操作后，只需运行即可即可立即安装它们

Of course, you can adjust the version number to whatever version you use. Once you've done this for all of your dependencies, you can install them at once by simply running

$ npm install

那应该解决它.

PS:在这种情况下，是否全局安装Express都无关紧要.全局安装仅适用于在整个系统范围内提供 express 引导程序. require 函数始终仅在本地应用程序上下文中搜索.

PS: It does not matter for this scenario whether you installed Express globally or not. A global installation is only good for having the express bootstrapper available system-wide. The require function always only searches within the local application context.

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