如何更改Angular服务注入实例

import { Injectable } from '@angular/core';

@Injectable({
  providedIn: 'root',
})
export class DataService {
  constructor(private http: HttpClient) { }
  
  // Service methods
}

// 更改注入实例的方法
const newServiceInstance = new DataService();
const injector = Injector.create({
  providers: [
    { provide: DataService, useValue: newServiceInstance }
  ]
});

// 获取现有实例并进行替换的方法
const injector = Injector.create();
const existingServiceInstance = injector.get(DataService);
existingServiceInstance.doSomething();
const newServiceInstance = new DataService();
injector.set(DataService, newServiceInstance);