没有HttpClient的提供者

从angular 4.4升级到5.0之后，并且将所有HttpModule和Http更新到HttpClientModule之后，我开始出现此错误。

我还再次添加了HttpModule以确保它不是由于某种依赖性，但不能解决问题

在app.module中，我都正确设置了

import { HttpModule } from '@angular/http';
import { HttpClientModule, HttpClient } from '@angular/common/http';
.
.
.
@NgModule({
    imports: [
        BrowserModule,
        HttpClientModule,
        HttpModule,
        BrowserAnimationsModule,
        FormsModule,
        AppRoutingModule,
.
.
.

我不知道该错误从何而来，或者我不知道如何获取该错误的内在信息。我也有一个警告（也放在下面）可能与它有关。

Error: StaticInjectorError[HttpClient]: 
  StaticInjectorError[HttpClient]: 
    NullInjectorError: No provider for HttpClient!
    at _NullInjector.get (vendor.js?v=mekBM8IVBK72-MIZOVSTJizGi_TD_xK3uhPOCRlEHwg:5665)
    at resolveToken (vendor.js?v=mekBM8IVBK72-MIZOVSTJizGi_TD_xK3uhPOCRlEHwg:5953)
    at tryResolveToken (vendor.js?v=mekBM8IVBK72-MIZOVSTJizGi_TD_xK3uhPOCRlEHwg:5895)
    at StaticInjector.get (vendor.js?v=mekBM8IVBK72-MIZOVSTJizGi_TD_xK3uhPOCRlEHwg:5766)
    at resolveToken (vendor.js?v=mekBM8IVBK72-MIZOVSTJizGi_TD_xK3uhPOCRlEHwg:5953)
    at tryResolveToken (vendor.js?v=mekBM8IVBK72-MIZOVSTJizGi_TD_xK3uhPOCRlEHwg:5895)
    at StaticInjector.get (vendor.js?v=mekBM8IVBK72-MIZOVSTJizGi_TD_xK3uhPOCRlEHwg:5766)
    at resolveNgModuleDep (vendor.js?v=mekBM8IVBK72-MIZOVSTJizGi_TD_xK3uhPOCRlEHwg:15328)
    at _createClass (vendor.js?v=mekBM8IVBK72-MIZOVSTJizGi_TD_xK3uhPOCRlEHwg:15373)
    at _createProviderInstance$1 (vendor.js?v=mekBM8IVBK72-MIZOVSTJizGi_TD_xK3uhPOCRlEHwg:15339)

警告信息：

./node_modules/@angular/Common/esm5/http.js
There are multiple modules with names that only differ in casing.
This can lead to unexpected behavior when compiling on a filesystem with other case-semantic.
Use equal casing. Compare these module identifiers:
* D:\XXX\node_modules\@angular\Common\esm5\http.js
    Used by 21 module(s), i. e.
    D:\XXX\node_modules\awesome-typescript-loader\dist\entry.js?silent=true!D:\XXX\node_modules\angular2-template-loader\index.js!D:\XXX\ClientApp\app\services\notification-endpoint.service.ts
* D:\XXX\node_modules\@angular\common\esm5\http.js
    Used by 1 module(s), i. e.
    D:\XXX\node_modules\awesome-typescript-loader\dist\entry.js?silent=true!D:\XXX\node_modules\angular2-template-loader\index.js!D:\XXX\ClientApp\app\app.module.ts
 @ ./node_modules/@angular/Common/esm5/http.js
 @ ./ClientApp/app/services/notification-endpoint.service.ts
 @ ./ClientApp/app/app.module.ts
 @ ./ClientApp/boot.browser.ts
 @ multi event-source-polyfill webpack-hot-middleware/client?path=__webpack_hmr&dynamicPublicPath=true ./ClientApp/boot.browser.ts

当前行为

StaticInjectorError[HttpClient]: StaticInjectorError[HttpClient]: NullInjectorError: No provider for HttpClient!

环境

Angular version: 5.0.0 and 5.0.1 (also 5.1 beta)

Browser:
- all

For Tooling issues:
- Node version: 8.5.0
- Platform:  windows

{
  "name": "X",
  "version": "1.0.0",
  "description": "X",
  "author": {
    "name": "X X",
    "email": "XX",
    "url": "X"
  },
  "homepage": "X",
  "dependencies": {
    "@angular/animations": "^5.1.0-beta.0",
    "@angular/common": "^5.1.0-beta.0",
    "@angular/compiler": "^5.1.0-beta.0",
    "@angular/compiler-cli": "^5.1.0-beta.0",
    "@angular/core": "^5.1.0-beta.0",
    "@angular/forms": "^5.1.0-beta.0",
    "@angular/http": "^5.1.0-beta.0",
    "@angular/platform-browser": "^5.1.0-beta.0",
    "@angular/platform-browser-dynamic": "^5.1.0-beta.0",
    "@angular/platform-server": "^5.1.0-beta.0",
    "@angular/router": "^5.1.0-beta.0",
    "@ngtools/webpack": "^1.8.0",
    "@ngx-translate/core": "^8.0.0",
    "@ngx-translate/http-loader": "^2.0.0",
    "@swimlane/ngx-datatable": "^11.0.3",
    "@types/jquery": "^3.2.16",
    "@types/webpack-env": "^1.13.2",
    "angular2-template-loader": "^0.6.2",
    "aspnet-webpack": "^2.0.1",
    "awesome-typescript-loader": "^3.3.0",
    "bootstrap": "^3.3.7",
    "bootstrap-datepicker": "^1.7.1",
    "bootstrap-select": "^1.12.4",
    "bootstrap-toggle": "^2.2.2",
    "bootstrap-vertical-tabs": "^1.2.2",
    "chart.js": "^2.7.1",
    "core-js": "^2.5.1",
    "css": "^2.2.1",
    "css-loader": "^0.28.7",
    "event-source-polyfill": "^0.0.11",
    "expose-loader": "^0.7.3",
    "extract-text-webpack-plugin": "^3.0.2",
    "file-loader": "^1.1.5",
    "font-awesome": "^4.7.0",
    "html-loader": "^0.5.1",
    "jquery": "^3.2.1",
    "json-loader": "^0.5.7",
    "ng2-charts": "^1.6.0",
    "ng2-toasty": "^4.0.3",
    "ngx-bootstrap": "^2.0.0-beta.8",
    "node-sass": "^4.6.0",
    "popper.js": "^1.12.6",
    "raw-loader": "^0.5.1",
    "rxjs": "^5.5.2",
    "sass-loader": "^6.0.6",
    "style-loader": "^0.19.0",
    "to-string-loader": "^1.1.5",
    "typescript": "^2.6.1",
    "url-loader": "^0.6.2",
    "web-animations-js": "^2.3.1",
    "webpack": "^3.8.1",
    "webpack-hot-middleware": "^2.20.0",
    "webpack-merge": "^4.1.1",
    "zone.js": "^0.8.18"
  },
  "devDependencies": {
    "@types/chai": "^4.0.4",
    "@types/jasmine": "^2.6.3",
    "chai": "^4.1.2",
    "jasmine-core": "^2.8.0",
    "karma": "^1.7.1",
    "karma-chai": "^0.1.0",
    "karma-chrome-launcher": "^2.2.0",
    "karma-cli": "^1.0.1",
    "karma-jasmine": "^1.1.0",
    "karma-jasmine-html-reporter": "^0.2.2",
    "karma-webpack": "^2.0.5"
  },
  "scripts": {
    "dev-build": "node node_modules/webpack/bin/webpack.js --config webpack.config.vendor.js",
    "test": "karma start ClientApp/test/karma.conf.js"
  }
}

webpack.config.js

const path = require('path');
const webpack = require('webpack');
const merge = require('webpack-merge');
const AotPlugin = require('@ngtools/webpack').AotPlugin;
const CheckerPlugin = require('awesome-typescript-loader').CheckerPlugin;

module.exports = (env) => {
    // Configuration in common to both client-side and server-side bundles
    const isDevBuild = !(env && env.prod);
    const sharedConfig = {
        stats: { modules: false },
        context: __dirname,
        resolve: { extensions: ['.js', '.ts'] },
        output: {
            filename: '[name].js',
            publicPath: 'dist/' // Webpack dev middleware, if enabled, handles requests for this URL prefix
        },
        module: {
            rules: [
                { test: /\.ts$/, use: isDevBuild ? ['awesome-typescript-loader?silent=true', 'angular2-template-loader'] : '@ngtools/webpack' },
                { test: /\.html$/, use: 'html-loader?minimize=false' },
                { test: /\.css$/, use: ['to-string-loader', isDevBuild ? 'css-loader' : 'css-loader?minimize'] },
                { test: /\.scss$/, use: ['to-string-loader', isDevBuild ? 'css-loader' : 'css-loader?minimize', 'sass-loader'] },
                { test: /\.(png|jpg|jpeg|gif|svg)$/, use: 'url-loader?limit=25000' }
            ]
        },
        plugins: [new CheckerPlugin()]
    };

    // Configuration for client-side bundle suitable for running in browsers
    const clientBundleOutputDir = './wwwroot/dist';
    const clientBundleConfig = merge(sharedConfig, {
        entry: { 'main-client': './ClientApp/boot.browser.ts' },
        output: { path: path.join(__dirname, clientBundleOutputDir) },
        plugins: [
            new webpack.DllReferencePlugin({
                context: __dirname,
                manifest: require('./wwwroot/dist/vendor-manifest.json')
            })
        ].concat(isDevBuild ? [
            // Plugins that apply in development builds only
            new webpack.SourceMapDevToolPlugin({
                filename: '[file].map', // Remove this line if you prefer inline source maps
                moduleFilenameTemplate: path.relative(clientBundleOutputDir, '[resourcePath]') // Point sourcemap entries to the original file locations on disk
            })
        ] : [
                // Plugins that apply in production builds only
                new webpack.optimize.UglifyJsPlugin(),
                new AotPlugin({
                    tsConfigPath: './tsconfig.json',
                    entryModule: path.join(__dirname, 'ClientApp/app/app.module#AppModule')
                })
            ])
    });

    return [clientBundleConfig];
};

webpack.config.vendor.js

const path = require('path');
const webpack = require('webpack');
const ExtractTextPlugin = require('extract-text-webpack-plugin');
const merge = require('webpack-merge');
const treeShakableModules = [
    '@angular/animations',
    '@angular/common',
    '@angular/compiler',
    '@angular/core',
    '@angular/forms',
    '@angular/http',
    '@angular/platform-browser',
    '@angular/platform-browser-dynamic',
    '@angular/router',
    'zone.js',
];
const nonTreeShakableModules = [
    'bootstrap',
    'core-js/client/shim',
    'web-animations-js',
    'event-source-polyfill',
    'jquery',
    '@swimlane/ngx-datatable/release/assets/icons.css',
    'ng2-toasty',
    'ng2-toasty/bundles/style-bootstrap.css',
    'ng2-charts',
    'ngx-bootstrap/modal',
    'ngx-bootstrap/tooltip',
    'ngx-bootstrap/popover',
    'ngx-bootstrap/dropdown',
    'ngx-bootstrap/carousel',
    'bootstrap-vertical-tabs/bootstrap.vertical-tabs.css',
    'bootstrap-toggle/css/bootstrap-toggle.css',
    'bootstrap-toggle/js/bootstrap-toggle.js',
    'bootstrap-select/dist/css/bootstrap-select.css',
    'bootstrap-select/dist/js/bootstrap-select.js',
    'bootstrap-datepicker/dist/css/bootstrap-datepicker3.css',
    'font-awesome/css/font-awesome.css'
];
const allModules = treeShakableModules.concat(nonTreeShakableModules);

module.exports = (env) => {
    const extractCSS = new ExtractTextPlugin('vendor.css');
    const isDevBuild = !(env && env.prod);
    const sharedConfig = {
        stats: { modules: false },
        resolve: { extensions: ['.js'] },
        module: {
            rules: [
                { test: /\.(gif|png|woff|woff2|eot|ttf|svg)(\?|$)/, use: 'url-loader?limit=100000' }
            ]
        },
        output: {
            publicPath: 'dist/',
            filename: '[name].js',
            library: '[name]_[hash]'
        },
        plugins: [
            new webpack.ProvidePlugin({ $: 'jquery', jQuery: 'jquery' }), // Maps these identifiers to the jQuery package (because Bootstrap expects it to be a global variable)
            new webpack.ContextReplacementPlugin(/\@angular\b.*\b(bundles|linker)/, path.join(__dirname, './ClientApp')), // Workaround for https://github.com/angular/angular/issues/11580
            new webpack.ContextReplacementPlugin(/angular(\\|\/)core(\\|\/)@angular/, path.join(__dirname, './ClientApp')), // Workaround for https://github.com/angular/angular/issues/14898
            new webpack.IgnorePlugin(/^vertx$/) // Workaround for https://github.com/stefanpenner/es6-promise/issues/100
        ]
    };

    const clientBundleConfig = merge(sharedConfig, {
        entry: {
            // To keep development builds fast, include all vendor dependencies in the vendor bundle.
            // But for production builds, leave the tree-shakable ones out so the AOT compiler can produce a smaller bundle.
            vendor: isDevBuild ? allModules : nonTreeShakableModules
        },
        output: { path: path.join(__dirname, 'wwwroot', 'dist') },
        module: {
            rules: [
                { test: /\.css(\?|$)/, use: extractCSS.extract({ use: isDevBuild ? 'css-loader' : 'css-loader?minimize' }) }
            ]
        },
        plugins: [
            extractCSS,
            new webpack.DllPlugin({
                path: path.join(__dirname, 'wwwroot', 'dist', '[name]-manifest.json'),
                name: '[name]_[hash]'
            })
        ].concat(isDevBuild ? [] : [
            new webpack.optimize.UglifyJsPlugin()
        ])
    });

    return [clientBundleConfig];
}

解决此问题的方法HttpClient是Angular通过HTTP与远程服务器通信的机制。

为了HttpClient在应用程序中随处可见，

1. 打开根AppModule，

2. 导入HttpClientModule从@angular/common/http，

   import { HttpClientModule } from '@angular/common/http';

3. 将其添加到@NgModule.imports数组。

   imports:[HttpClientModule, ]

您尚未在模块中提供提供程序：

<strike>import { HttpModule } from '@angular/http';</strike>
import { HttpClientModule, HttpClient } from '@angular/common/http';

@NgModule({
  imports: [
    BrowserModule,
    HttpClientModule,
    BrowserAnimationsModule,
    FormsModule,
    AppRoutingModule
  ],
  providers: [ HttpClientModule, ... ]
  // ...
})
export class MyModule { /* ... */ }

在测试中使用HttpClient

您需要HttpClientTestingModule在运行ng test并获取“ No Client for HttpClient”错误时将添加到TestBed配置中：

// Http testing module and mocking controller
import { HttpClientTestingModule, HttpTestingController } from '@angular/common/http/testing';

// Other imports
import { TestBed } from '@angular/core/testing';
import { HttpClient, HttpErrorResponse } from '@angular/common/http';

describe('HttpClient testing', () => {
  let httpClient: HttpClient;
  let httpTestingController: HttpTestingController;

  beforeEach(() => {
    TestBed.configureTestingModule({
      imports: [ HttpClientTestingModule ]
    });

    // Inject the http service and test controller for each test
    httpClient = TestBed.get(HttpClient);
    httpTestingController = TestBed.get(HttpTestingController);
  });

  it('works', () => {
  });
});

您收到HttpClient的错误，因此缺少HttpClientModule。

您应该像这样将其导入app.module.ts文件中-

import { HttpClientModule } from '@angular/common/http';

并在NgModule Decorator中像这样提到它-

@NgModule({
...
imports:[ HttpClientModule ]
...
})

如果这仍然不起作用，请尝试清除浏览器的Cookie，然后尝试重新启动服务器。希望它可以工作，我遇到了同样的错误。

我有同样的问题。浏览并努力解决问题后，找到以下解决方案

import { HttpModule } from '@angular/http';
import { HttpClientModule } from '@angular/common/http';

imports: [
  HttpModule,
  HttpClientModule
]

导入HttpModule并HttpClientModule在app.module.ts中并添加到上述导入中。

通过进行以下更改，我也面临着类似的问题，它对我有用

在app.modules.ts中

import {HttpClientModule} from '@angular/common/http' 

并在相应的服务等级中

import { HttpClient } from '@angular/common/http'

构造函数应如下所示

constructor(private http: HttpClient, private xyz: xyzService) {}

在测试文件中

import { HttpClientTestingModule } from '@angular/common/http/testing'

  beforeEach(() => TestBed.configureTestingModule({
    imports: [HttpClientTestingModule]
  }));

我面临着同样的问题，有趣的是，我同时打开了两个项目，更改了错误的app.modules.ts文件。

首先，检查一下。

更改之后，将以下代码添加到app.module.ts文件中

import { HttpClientModule } from '@angular/common/http';

之后，将以下内容添加到app.module.ts文件中的imports数组中

  imports: [
    HttpClientModule,....
  ],

现在你应该没事了！

在将使用HTTPClient的服务注入到类中后，出现此错误。该类再次在服务中使用，因此创建了循环依赖项。我可以使用警告编译应用程序，但是在浏览器控制台中发生了错误

“没有HttpClient的提供者！（MyService-> HttpClient）”

它破坏了应用程序。

这有效：

import { HttpClient, HttpClientModule, HttpHeaders } from '@angular/common/http';
import { MyClass } from "../classes/my.class";

@Injectable()
export class MyService {
  constructor(
    private http: HttpClient
  ){
    // do something with myClass Instances
  }      
}
.
.
.
export class MenuItem {
  constructor(

  ){}
}

这会破坏应用程序

import { HttpClient, HttpClientModule, HttpHeaders } from '@angular/common/http';
import { MyClass } from "../classes/my.class";

@Injectable()
export class MyService {
  constructor(
    private http: HttpClient
  ){
    // do something with myClass Instances
  }      
}
.
.
.
import { MyService } from '../services/my.service';
export class MyClass {
  constructor(
    let injector = ReflectiveInjector.resolveAndCreate([MyService]);
    this.myService = injector.get(MyService);
  ){}
}

在MyClass中注入MyService之后，我得到了循环依赖警告。CLI仍会使用此警告进行编译，但该应用程序不再起作用，并且在浏览器控制台中给出了错误。因此，在我的情况下，它不必使用@NgModule进行任何操作，而是使用循环依赖项。如果您的问题仍然存在，我建议解决区分大小写的命名警告。

我遇到了同样的问题，然后在我的app.module.ts中以这种方式更新了文件，

import { HttpModule } from '@angular/http';
import { HttpClientModule } from '@angular/common/http';

并以这种方式在我的@NgModule imports []数组中的同一文件（app.module.ts）中，

HttpModule,
HttpClientModule

我发现了更苗条的问题。请按照以下步骤将HttpClientModule导入到您的app.module.ts文件中：

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

import { AppComponent } from './app.component';
import { HttpClientModule } from '@angular/common/http';

@NgModule({
  declarations: [
    AppComponent
],

imports: [
    BrowserModule,
    HttpClientModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

在有角的github页面中，讨论了此问题并找到了解决方案。 https://github.com/angular/angular/issues/20355

app.module.ts中的import和provider中的Add HttpModule和HttpClientModule解决了该问题。 进口 ->import {HttpModule} from "@angular/http"; import {HttpClientModule} from "@angular/common/http";

只需导入HttpModule和HttpClientModule：

import { HttpModule } from '@angular/http';
import { HttpClientModule } from '@angular/common/http';

不需要HttpClient。

我有类似的问题。对我来说，解决方法是在HttpClient Module之前导入HttpModule：

import { HttpModule } from '@angular/http';
import { HttpClientModule } from '@angular/common/http';
.
.
.
imports: [
  BrowserModule,
  HttpModule,
  HttpClientModule
],

就我而言，使用位于npm包中的angular模块的服务（该服务需要注入）时发生错误HttpClient。安装npm软件包时，node_modules由于npm的版本冲突处理（engi-sdk-client该模块包含服务），在软件包目录中创建了一个重复目录：

显然，对的依赖关系HttpClient无法正确解析，因为HttpClientModule注入服务的位置（位于重复node_modules目录中）和注入的位置app.module（正确的位置）node_modules）不匹配。

node_modules由于错误，我在包含重复目录的其他设置中也遇到了此错误npm install调用，。

这种有缺陷的设置还会导致所描述的运行时异常No provider for HttpClient!。

TL; DR; node_modules如果没有其他解决方案，请检查目录是否重复！

就我而言，我发现一旦重新构建应用程序便可以正常工作。

我已经导入了HttpClientModule以前的文章中指定的，但是仍然出现错误。我停止了服务器，重建了应用程序（ng serve），它开始工作了。