Angular 2依赖项注入在服务上不起作用

我试图从Angular 2中的UserService获取静态数据。从文档中看，一切正常，但由于某些原因，它不起作用

这是我的UserComponent.ts

import {Component ,OnInit } from '@angular/core';
import {UsersService} from './users.service';


    @Component({
      selector: 'users',
      template: `<h3>Users </h3>
      <ul> 
        <li *ngFor="let user of users">{{user}}</li>
      </ul>
       `,
      providers:[UsersService]
    })
    export class UsersComponent {
        users;
        title;

        construct( usersService: UsersService){
           this.users=usersService.getUsers();
// i also tried this but no luck. this.users = this.usersService.getUsers();
        }

    }

正如预期的那样，它的产出应该是

<h3>Users </h3>
  <ul>  
    <li>Krishna</li>
    <li>Ravi</li>
    <li>Hari</li>
    <li>etc</li>
  </ul>

用户

克里希纳
拉维
哈里
等

---

但它不会在*ngFor循环中重复。我也打印了{{users}}，结果返回空。请告诉我这里有什么问题

构造函数

有拼写错误

export class UsersComponent {
  users;
  title;

  constructor( private usersService: UsersService) {        
  }

  ngOnInit() {
    this.users = this.usersService.getUsers();
  }
}

constructor

export class UsersComponent {
  users;
  title;

  constructor( private usersService: UsersService) {        
  }

  ngOnInit() {
    this.users = this.usersService.getUsers();
  }
}

非常感谢，非常感谢。