如何在不使用构造函数的情况下实例化angular 2服务？

我正在尝试使用我的ApiService类处理另一个类中的api请求，但无法使其工作。 问题是ApiService构造函数需要HttpClient，这意味着我不能只使用如下内容：http=new-ApiServicenew-HttpClient，globals

ApiService：

import { Injectable } from '@angular/core';
import { HttpClient, HttpRequest } from '@angular/common/http';
import { Globals } from './globals';

@Injectable({
  providedIn: 'root'
})
export class ApiService {
  constructor(private http: HttpClient, private globals: Globals) {}

  get(url : string, params: {}){
    return this.http.get(this.globals.api_url.concat(url), {params: params});
  }

  ...
}

export class UploadAdapter {
    http: ApiService;
    constructor() {}

    upload() {
           //Here I get an error saying can't get post of undefined 
       http.post('api_url'.concat('/medias/upload'), {}, {})
         .subscribe((data) => {
            //do stuff here.
         });
    }



}

类调用服务：

import { Injectable } from '@angular/core';
import { HttpClient, HttpRequest } from '@angular/common/http';
import { Globals } from './globals';

@Injectable({
  providedIn: 'root'
})
export class ApiService {
  constructor(private http: HttpClient, private globals: Globals) {}

  get(url : string, params: {}){
    return this.http.get(this.globals.api_url.concat(url), {params: params});
  }

  ...
}

export class UploadAdapter {
    http: ApiService;
    constructor() {}

    upload() {
           //Here I get an error saying can't get post of undefined 
       http.post('api_url'.concat('/medias/upload'), {}, {})
         .subscribe((data) => {
            //do stuff here.
         });
    }



}

---

您没有在组件中注入服务

您的UploadAdapter构造函数应该如下所示

constructorprivate http:ApiService{}

您还需要使用

这是http.post

而不是

---

http.post

实例化一个没有构造函数的类听起来像是胡说八道。嗨，Asim，问题是UploadAdapter不是一个组件，而是另一个处理与api通信的服务本身。我不能将ApiService注入UploadAdapter的构造函数中，否则在实例化它时，我需要使用以下内容：new UploadAdapternew ApiServicenew HttpClient，new Globals