解决Angular2 ，SystemJS XHR error

初学Angular2，跟着Angular2中文网学到HTTP这一节时出现了一个异常：

GET http://localhost:3000/traceur 404 (Not Found)
Error: (SystemJS) XHR error (404 Not Found) loading http://localhost:3000/traceur
        Error: XHR error (404 Not Found) loading http://localhost:3000/traceur
            at XMLHttpRequest.wrapFn [as _onreadystatechange] (http://localhost:3000/node_modules/zone.js/dist/zone.js:698:29)
            at ZoneDelegate.invokeTask (http://localhost:3000/node_modules/zone.js/dist/zone.js:265:35)
            at Zone.runTask (http://localhost:3000/node_modules/zone.js/dist/zone.js:154:47)
            at XMLHttpRequest.ZoneTask.invoke (http://localhost:3000/node_modules/zone.js/dist/zone.js:335:33)

在Github的Issue中找到了答案：

https://github.com/angular/angular/issues/11358

最终解决方案如下：

1、修改systemjs.config.js文件如下：（将angular-in-memory-web-api修改为angular2-in-memory-web-api）

(function (global) {
  System.config({
    paths: {
      // paths serve as alias
      'npm:': 'node_modules/'
    },
    // map tells the System loader where to look for things
    map: {
      // our app is within the app folder
      app: 'app',
      // angular bundles
      '@angular/core': 'npm:@angular/core/bundles/core.umd.js',
      '@angular/common': 'npm:@angular/common/bundles/common.umd.js',
      '@angular/compiler': 'npm:@angular/compiler/bundles/compiler.umd.js',
      '@angular/platform-browser': 'npm:@angular/platform-browser/bundles/platform-browser.umd.js',
      '@angular/platform-browser-dynamic': 'npm:@angular/platform-browser-dynamic/bundles/platform-browser-dynamic.umd.js',
      '@angular/http': 'npm:@angular/http/bundles/http.umd.js',
      '@angular/router': 'npm:@angular/router/bundles/router.umd.js',
      '@angular/forms': 'npm:@angular/forms/bundles/forms.umd.js',
      // other libraries
      'rxjs':                      'npm:rxjs',
      'angular2-in-memory-web-api': 'npm:angular2-in-memory-web-api',
    },
    // packages tells the System loader how to load when no filename and/or no extension
    packages: {
      app: {
        main: './main.js',
        defaultExtension: 'js'
      },
      rxjs: {
        defaultExtension: 'js'
      },
      'angular2-in-memory-web-api': {
        main: './index.js',
        defaultExtension: 'js'
      }
    }
  });
})(this);

2、修改package.json文件如下：（将angular-in-memory-web-api修改为angular2-in-memory-web-api）

{
  "name": "angular2Demo",
  "version": "1.0.0",
  "scripts": {
    "start": "tsc && concurrently \"tsc -w\" \"lite-server\" ",
    "lite": "lite-server",
    "postinstall": "typings install",
    "tsc": "tsc",
    "tsc:w": "tsc -w",
    "typings": "typings"
  },
  "licenses": [
    {
      "type": "MIT",
      "url": "https://github.com/angular/angular.io/blob/master/LICENSE"
    }
  ],
  "dependencies": {
    "@angular/common": "~2.1.0",
    "@angular/compiler": "~2.1.0",
    "@angular/core": "~2.1.0",
    "@angular/forms": "~2.1.0",
    "@angular/http": "~2.1.0",
    "@angular/platform-browser": "~2.1.0",
    "@angular/platform-browser-dynamic": "~2.1.0",
    "@angular/router": "~3.1.0",
    "@angular/upgrade": "~2.1.0",
    "angular2-in-memory-web-api": "0.0.21",
    "bootstrap": "^3.3.7",
    "core-js": "^2.4.1",
    "reflect-metadata": "^0.1.8",
    "rxjs": "5.0.0-beta.12",
    "systemjs": "0.19.39",
    "zone.js": "^0.6.25"
  },
  "devDependencies": {
    "concurrently": "^3.0.0",
    "lite-server": "^2.2.2",
    "typescript": "^2.0.3",
    "typings":"^1.4.0"
  }
}

3、修改app.module.ts中InMemoryWebApiModule的导入方式）

import { InMemoryWebApiModule } from 'angular2-in-memory-web-api';