可以的。简略代码如下:
html:

  <input type="text"  formControlName="account">
  <div *ngIf="formErrors.account" class="alert alert-danger">{{ formErrors.account }}</div>
  
  <input type="password"  formControlName="password">
  <div *ngIf="formErrors.password" class="alert alert-danger">{{ formErrors.password }}</div>
  

ts:

editForm: FormGroup;
formErrors = {
    'account': '',
    'password': ''
};

validationMessages = {
    'account': {
        'required': '请输入用户名',
        'maxlength': '用户名不能超过20位'
    },
    'password': {
        'required': '请输入密码',
        'minlength': '密码至少6位',
        'maxlength': '密码必须小于16位',
        'pattern': '密码需要包含大小写和数字'
    }
};

 ngOnInit() {
 
 this.editForm = new FormGroup({
            account: new FormControl('', [Validators.required, Validators.maxLength(20)]),
            password: new FormControl('', [
                Validators.minLength(6),
                Validators.maxLength(16),
                Validators.required,
                Validators.pattern('^(?=.*[A-Z])(?=.*[0-9])(?=.*[a-z])[0-9a-zA-Z]{6,16}$')
            ])
        });
        
  this.editForm.valueChanges.subscribe(() => this.onValueChanged());   // 监听每次输入内容，获得错误信息
  }
  
  onValueChanged() {
    for (const item in this.formErrors) {
        this.formErrors[item] = '';
        for (const key in this.editForm.get(item).errors) {
            this.formErrors[item] += this.validationMessages[item][key] + ' ';
        }
    }
}