angular中的service注入问题

Question

service代码如下

import { Injectable } from '@angular/core';
import { FatherModule } from './father/father.module'

@Injectable({
  providedIn: FatherModule
})
export class InnerService {

  constructor() { }
  sayHello(){
    console.log('good morning')
  }
}

father.module.ts代码如下

import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import { FatherComponent } from './father.component'
import { SonComponent } from '../son/son.component'


@NgModule({
  declarations: [
    SonComponent
  ],
  imports: [
    CommonModule
  ],
  providers:[]
})
export class FatherModule { }

出现了如下错误

 StaticInjectorError(Platform: core)[FatherComponent -> InnerService]: 
    NullInjectorError: No provider for InnerService!
    at

Answer 1

没有把module放入appModule的import中

Answer 2

InnerService需要注入进入，在:

providers: [ InnerService ]