Angular2:如何将两个或多个验证器应用于同一控件？

import { Component } from '@angular/core';
import { FormControl, Validators } from '@angular/forms';

@Component({
  selector: 'app-example',
  template: `
    <form>
      <input type="text" [formControl]="myControl">
      <div *ngIf="myControl.hasError('required')">必填项</div>
      <div *ngIf="myControl.hasError('minlength')">最小长度为5</div>
    </form>
  `
})
export class ExampleComponent {
  myControl = new FormControl('', Validators.compose([
    Validators.required,
    Validators.minLength(5)
  ]));
}