本文带大家了解一下Angular里的HttpClientModule控制模块，介绍一下HttpClientModule控制模块使用方法，希望能帮助到大家！
该控制模块用以推送 Http 要求，用以发送数据的方法都回到 Observable 目标。【有关实例教程强烈推荐：《angular教程》】
1. 快速开始
引进 HttpClientModule 控制模块
// app.module.ts
import { httpClientModule } from '@angular/common/http';
imports: [
httpClientModule
]// app.component.ts
import { HttpClient } from '@angular/common/http';
export class AppComponent {
constructor(private http: HttpClient) {}
}发送数据
import { HttpClient } from "@angular/common/http"
export class AppComponent implements OnInit {
constructor(private http: HttpClient) {}
ngOnInit() {
this.getUsers().subscribe(console.log)
}
getUsers() {
return this.http.get("https://jsonplaceholder.typicode.com/users")
}
}2. 请求方法
this.http.get(url [, options]);
this.http.post(url, data [, options]);
this.http.delete(url [, options]);
this.http.put(url, data [, options]);
this.http.get<Post[]>('/getAllPosts')
.subscribe(response => console.log(response))3. 请求参数
HttpParams 类
export declare class HttpParams {
constructor(options?: HttpParamsOptions);
has(param: string): boolean;
get(param: string): string | null;
getAll(param: string): string[] | null;
keys(): string[];
append(param: string, value: string): HttpParams;
set(param: string, value: string): HttpParams;
delete(param: string, value?: string): HttpParams;
toString(): string;
}HttpParamsOptions 插口
declare interface HttpParamsOptions {
fromString?: string;
fromObject?: {
[param: string]: string | ReadonlyArray<string>;
};
encoder?: HttpParameterCodec;
}应用实例
import { HttpParams } from '@angular/common/http';
let params = new HttpParams({ fromObject: {name: "zhangsan", age: "20"}})
params = params.append("sex", "male")
let params = new HttpParams({ fromString: "name=zhangsan&age=20"})4. 请求头
请求头字段名的建立需要使用 HttpHeaders 类，在类实例对象下边有各种各样的实际操作请求头的办法。
export declare class HttpHeaders {
constructor(headers?: string | {
[name: string]: string | string[];
});
has(name: string): boolean;
get(name: string): string | null;
keys(): string[];
getAll(name: string): string[] | null;
append(name: string, value: string | string[]): HttpHeaders;
set(name: string, value: string | string[]): HttpHeaders;
delete(name: string, value?: string | string[]): HttpHeaders;
}let headers = new HttpHeaders({ test: "Hello" })5. 回应具体内容
declare type HttpObserve = 'body' | 'response';
// response 载入详细响应体
// body 载入服务端返回数据信息
this.http.get(
"https://jsonplaceholder.typicode.com/users",
{ observe: "body" }
).subscribe(console.log)6. 回调函数
回调函数是 Angular 运用中全局性捕捉和调整 HTTP 请求和响应的形式。（Token、Error）
回调函数将只阻拦应用 HttpClientModule 控制模块发出来的要求。
$ ng g interceptor <name>
6.1 要求阻拦
@Injectable()
export class AuthInterceptor implements HttpInterceptor {
constructor() {}
// 阻拦方式
intercept(
// unknown 特定请求体 (body) 的种类
request: HttpRequest<unknown>,
next: HttpHandler
// unknown 特定回应具体内容 (body) 的种类
): Observable<HttpEvent<unknown>> {
// 复制并改动请求头
const req = request.clone({
setHeaders: {
Authorization: "Bearer xxxxxxx"
}
})
// 根据调用函数将修订后的请求头回发送给运用
return next.handle(req)
}
}6.2 回应阻拦
@Injectable()
export class AuthInterceptor implements HttpInterceptor {
constructor() {}
// 阻拦方式
intercept(
request: HttpRequest<unknown>,
next: HttpHandler
): Observable<any> {
return next.handle(request).pipe(
retry(2),
catchError((error: HttpErrorResponse) => throwError(error))
)
}
}6.3 回调函数引入
import { AuthInterceptor } from "./auth.interceptor"
import { HTTP_INTERCEPTORS } from "@angular/common/http"
@NgModule({
providers: [
{
provide: HTTP_INTERCEPTORS,
useClass: AuthInterceptor,
multi: true
}
]
})7. Angular Proxy
在工程项目的目录下建立 proxy.conf.json 文档并加入如下所示编码
{
"/api/*": {
"target": "http://localhost:3070",
"secure": false,
"changeOrigin": true
}
}
/api/：在运用中传出以
/api开头要求走此代理商target：服务端
URLsecure：假如服务端
URL的协议是https，该项需要为truechangeOrigin：假如服务端并不是
localhost， 该项需要为true
特定 proxy 环境变量 (方法一)
// package.json
"scripts": {
"start": "ng serve --proxy-config proxy.conf.json",
}特定 proxy 环境变量 (方法二)
// angular.json 文档中
"serve": {
"options": {
"proxyConfig": "proxy.conf.json"
},大量程序编写基本知识，请访问：编程学习！！
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