angular - 找不到 HttpClient 的提供者
從 Angular 4.4 升級到 5.0 並更新所有 HttpModule 和 Http 到 HttpClientModule 後，我開始收到這個錯誤。
我也再次添加了 HttpModule，以確保問題不是由於某些依賴造成的，但這並沒有解決問題
在 app.module 中，我已經全部正確設置
import { HttpModule } from '@angular/http';
import { HttpClientModule, HttpClient } from '@angular/common/http';
.
.
.
@NgModule({
imports: [
BrowserModule,
HttpClientModule,
HttpModule,
BrowserAnimationsModule,
FormsModule,
AppRoutingModule,
.
.
.
我不知道這個錯誤是從哪裡來的，或者我完全不知道如何深入了解它。我也有一個警告（也附在下面）可能和它有關。
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)
警告訊息：
./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
當前行為
StaticInjectorError[HttpClient]: StaticInjectorError[HttpClient]: NullInjectorError: 沒有 HttpClient 的提供者！
環境
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];
}
答案＃1
為了解決這個問題，HttpClient 是 Angular 用來通過 HTTP 與遠端伺服器進行通訊的機制。
要讓 HttpClient 在應用程式的各處都可用，
打開根目錄
AppModule，從
@angular/common/http匯入HttpClientModule，import { HttpClientModule } from '@angular/common/http';將它添加到
@NgModule.imports陣列中。imports:[HttpClientModule, ]
答案＃2
您尚未在您的模組中提供提供者：
<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 { /* ... */ }
在測試中使用 HttpClient
當執行 ng test 並遇到「No provider for HttpClient」錯誤時，您需要將 HttpClientTestingModule 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', () => {
});
});
答案＃3
隨著 Angular 最近的變動（Angular 17），已經沒有 app.module 檔案。因此在新的結構中，你將需要在 app.config 檔案中更新它並添加
提供HttpClient()
import { ApplicationConfig } from '@angular/core';
import { provideHttpClient } from '@angular/common/http'
import { provideRouter, withHashLocation } from '@angular/router';
import { routes } from './app.routes';
export const appConfig: ApplicationConfig = {
providers: [
provideRouter(routes, withHashLocation()),
provideHttpClient()
]
};
或者如果你想添加認證攔截器，你可以這樣做
import { ApplicationConfig } from '@angular/core';
import { provideHttpClient, withInterceptors } from '@angular/common/http'
import { provideRouter, withHashLocation } from '@angular/router';
import { routes } from './app.routes';
export const appConfig: ApplicationConfig = {
providers: [
provideRouter(routes, withHashLocation()),
provideHttpClient(withInterceptors([authenticationInterceptor]))
]
};
攔截器可以這樣宣告
import { HttpHandlerFn, HttpInterceptorFn, HttpRequest } from "@angular/common/http";
export const authenticationInterceptor: HttpInterceptorFn = (req: HttpRequest<unknown>, next:
HttpHandlerFn) => {
const modifiedReq = req.clone({
headers: req.headers.set('Authorization', `Bearer ${sessionStorage.getItem('token')}`),
});
return next(modifiedReq);
};
答案＃4
你因為 HttpClient 出現錯誤，所以你缺少了 HttpClientModule。
你應該像這樣在 app.module.ts 文件中匯入它 -
import { HttpClientModule } from '@angular/common/http';
並在 NgModule 裝飾器中這樣提及 -
@NgModule({
...
imports:[ HttpClientModule ]
...
})
如果這甚至都不行，試著清除瀏覽器的 Cookie 並嘗試重新啟動你的伺服器。希望它能有效，我之前也遇到過相同的錯誤。
答案＃5
只需在 app.module.ts 文件的 'imports' 陣列中添加 HttpClientModule。
...
import {HttpClientModule} from '@angular/common/http'; // add this line
@NgModule({
declarations: [
AppComponent,
HeaderComponent
],
imports: [
BrowserModule,
HttpClientModule, //add this line
],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule { }
然後你可以透過建構函式注入在你的專案中使用 HttpClient
import {HttpClient} from '@angular/common/http';
export class Services{
constructor(private http: HttpClient) {}
答案＃6
我遇到了同樣的問題。在瀏覽和努力解決問題後，找到了以下解決方案
import { HttpModule } from '@angular/http';
import { HttpClientModule } from '@angular/common/http';
imports: [
HttpModule,
HttpClientModule
]
在 app.module.ts 中匯入 HttpModule 和 HttpClientModule，並如上所述添加到 imports 中。
答案＃7
步驟 1：在 app.module.ts 中導入 HttpClientModule：
import { HttpClientModule} from '@angular/common/http';
第 2 步：在模組匯入中加入 HttpClientModule：
@NgModule({
declarations: [
...
],
imports: [
HttpClientModule
],
providers: [
....
],
bootstrap: [AppComponent]
})
答案＃8
我也透過進行以下更改遇到了類似的問題，這對我有效
在 app.modules.ts 中
import {HttpClientModule} from '@angular/common/http'
以及在相應的服務類別中
import { HttpClient } from '@angular/common/http'
建構函式應該如下所示
constructor(private http: HttpClient, private xyz: xyzService) {}
在測試文件中
import { HttpClientTestingModule } from '@angular/common/http/testing'
beforeEach(() => TestBed.configureTestingModule({
imports: [HttpClientTestingModule]
}));
答案＃9
前往 app.module.ts
import import { HttpClientModule } from '@angular/common/http';
和
在 imports 下添加 HttpClientModule
應該看起來像這樣
imports: [BrowserModule, IonicModule.forRoot(), AppRoutingModule,HttpClientModule]
答案＃10
這個問題更多是由於在根模組中未註冊所需的服務，即 HttpClientModule，即 NgModule。
你缺少 HttpClientModule，因此你在使用 HttpClient 時收到錯誤
你應該在 app.module.ts 文件中如下導入它，
import { HttpClientModule } from '@angular/common/http';
並像這樣在 NgModule 裝飾器中提及它 -
@NgModule({
...
imports:[ HttpClientModule ]
...
})
希望它能奏效。請參考下方圖片以獲取更多想法。
答案＃11
我遇到了同樣的問題，有趣的是我同時打開了兩個專案，我改錯了 app.modules.ts 檔案。
首先，檢查那個。
在那個更改之後，將以下程式碼添加到 app.module.ts 檔案中
import { HttpClientModule } from '@angular/common/http';
之後在 app.module.ts 文件的 imports 陣列中添加以下內容
imports: [
HttpClientModule,....
],
現在你應該沒事了！
答案＃12
我也遇到同樣的問題，然後在我的 app.module.ts 中，我以這種方式更新了文件，
import { HttpModule } from '@angular/http';
import { HttpClientModule } from '@angular/common/http';
並且在同一個檔案 (app.module.ts) 中，我在 @NgModule 的 imports[] 陣列中是這麼寫的，
HttpModule,
HttpClientModule
答案＃13
在將使用 HTTPClient 的服務注入到一個類後，我收到了這個錯誤。該類又在服務中被使用，因此產生了循環依賴。我可以在有警告的情況下編譯應用程式，但在瀏覽器控制台中出現了錯誤。
「沒有 HttpClient 的提供者！(MyService -> HttpClient)」
而且它弄壞了應用程式。
這有效：
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(
){}
}
這會破壞應用程式
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);
){}
}
在將 MyService 注入 MyClass 後，我收到了循環依賴的警告。CLI 儘管有這個警告仍然編譯，但應用程式不再運作，並且錯誤出現在瀏覽器控制台中。所以在我的情況下，這與 @NgModule 無關，而是與循環依賴有關。如果你的問題仍然存在，我建議解決區分大小寫的命名警告。
答案＃14
透過在 imports 區段中新增 HttpClientModule 提供者來修正
import { HttpClientModule } from '@angular/common/http';
@NgModule({
declarations: [
AppComponent,
],
imports: [
BrowserModule,
AppRoutingModule,
HttpClientModule,
]
})
這個我們需要添加在 src -> app -> app.module.ts 文件中。
答案＃15
在 Angular 17 - NullInjectorError：找不到 _HttpClient 的提供者！請到你的 app.config.ts，在 providers 陣列內添加：
provideHttpClient()
import { ApplicationConfig } from '@angular/core';
import { provideRouter } from '@angular/router';
import { routes } from './app.routes';
import { provideClientHydration } from '@angular/platform-browser';
import { provideAnimationsAsync } from '@angular/platform-browser/animations/async';
import { provideHttpClient } from '@angular/common/http';
export const appConfig: ApplicationConfig = {
providers: [
provideRouter(routes),
provideClientHydration(),
provideAnimationsAsync(),
provideHttpClient(),
],
};
這解決了我的錯誤
答案＃16
我發現了一個更棘手的問題。請在你的 app.module.ts 文件中按如下方式導入 HttpClientModule：
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 { }
答案＃17
在 app.module.ts 的 import 區段，你需要新增 HttpClientModule。以下是範例
import { HttpClientModule } from '@angular/common/http';
@NgModule({
declarations: [
AppComponent
],
imports: [
BrowserModule,
BrowserAnimationsModule,
HttpClientModule, // This is where you need to add
FormsModule,
...