获取空的json数据

Question

我正在尝试从 url 获取 json 数据，但我无法获取任何数据。 它只是显示一个空数组。你觉得我错过了什么 在这里？

service.ts

这是 service.ts。我正在尝试从“https://jsonplaceholder.typicode.com/posts”获取数据。

import { Injectable } from '@angular/core';
import{UserCreation} from '../../models/user-creation.model';
import{Observable} from 'rxjs/Observable';
import{of} from 'rxjs/observable/of';
import{catchError,map,tap} from 'rxjs/operators';
import{HttpClient,HttpHeaders} from '@angular/common/http';

const httpOptions={
    headers:new HttpHeaders({'Content-Type':'application/json'})
};

@Injectable({
providedIn: 'root'
})

export class UserCreationService{

//Create constructor to get Http instance
constructor(private http:HttpClient) { }

private usersUrl:'https://jsonplaceholder.typicode.com/posts';

getUsers():Observable<UserCreation[]>{

return this.http.get<UserCreation[]>(this.usersUrl).pipe(
tap(receivedUsers 
=>console.log(`receivedUsers=${JSON.stringify(receivedUsers)}`)),
catchError(error=>of([]))
);
}

app.component.ts

这是component.ts文件

import { Component, OnInit } from '@angular/core';
import { Http, Response } from '@angular/http';
import { UserCreationService } from '../../common/services/user- 
creation.service';


@Component({
selector: 'app',
templateUrl: './app.component.html',
styleUrls: ['./app-component.css']
})

export class AppComponent implements OnInit {

allUsers: UserCreation[];

constructor(private userService: UserCreationService) { }

getUsersFromServices():void{
this.userService.getUsers().subscribe(
  (Users)=>{
    this.allUsers=Users;
    console.log(`this.allUsers = ${JSON.stringify(this.allUsers)}`);

  }
 )
}

ngOnInit(): void {
this.getUsersFromServices();
}

Answer 1

这里有错字 - private usersUrl:'https://jsonplaceholder.typicode.com/posts';。

应该是=，而不是像这样的: - private usersUrl='https://jsonplaceholder.typicode.com/posts';。

或者更好的方式private usersUrl:string = 'https://jsonplaceholder.typicode.com/posts';