Angular 6 Observable Http获取异步

Question

我是有经验的新手，我在从http客户端获取异步数据时遇到问题，我的代码是

用户服务：

  getAll(): Observable<User[]> {
    return this.http.get<User[]>(`${this.API_URL}/users`);
  }

  registerUser(user: User) {
    return this.http.post(`${this.API_URL}/api/auth/registerUser`, user);
  }

用户模型：

export class User {
  id: number;
  name: string;
  username: string;
  surname: string;
  email: string;
  password: string;
  street: string;
  numberStreet: string;
  postalCode: string;
  city: string;
}

用户列表组件：

export class UserListComponent implements OnInit {

  public data: User[];

  constructor(private userService: UserService, private modalService: NgbModal) {
  }

  ngOnInit() {
    this.getListUsers();
  }

  getListUsers() {
    this.userService.getAll().subscribe(
      restItems => {
        this.data = restItems;
      }
    );
  }

this.userService.registerUser(this.registerForm.value)
}

现在，如果我添加用户并在数据库中发送帖子，则存储用户，但在前面它不会出现。重新加载页面后工作的用户列表