使用LocalStorage或SessionStorage将表单数据保存在浏览器中，在Angular应用程序重新加载时恢复表单数据。以下是一个示例实现：

//service.ts import { Injectable } from '@angular/core';

@Injectable() export class FormDataService { private formDataKey = 'my_app_form_data';

constructor() { }

saveData(formData: any): void { localStorage.setItem(this.formDataKey, JSON.stringify(formData)); }

getData(): any { const data = localStorage.getItem(this.formDataKey); return data ? JSON.parse(data) : null; }

clearData(): void { localStorage.removeItem(this.formDataKey); } }

//component.ts import { Component, OnInit } from '@angular/core'; import { FormGroup, FormBuilder, Validators } from '@angular/forms'; import { FormDataService } from '../services/form-data.service';

@Component({ selector: 'app-my-form', templateUrl: './my-form.component.html', styleUrls: ['./my-form.component.css'] }) export class MyFormComponent implements OnInit { myForm: FormGroup;

constructor( private fb: FormBuilder, private formDataService: FormDataService ) { }

ngOnInit() { this.myForm = this.fb.group({ name: ['', Validators.required], email: ['', Validators.required] });

const savedData = this.formDataService.getData();
if (savedData) {
  this.myForm.patchValue(savedData);
}

}

onSubmit() { if (this.myForm.valid) { this.formDataService.saveData(this.myForm.value); } }

ngOnDestroy() { this.formDataService.clearData(); } }

在上面的示例中，FormDataService使用LocalStorage存储表单数据，并在MyFormComponent组件的OnInit方法中从LocalStorage中检索数据。然后，使用FormGroup的patchValue方法将数据填充到表单中。

在MyFormComponent的onSubmit方法中，如果表单有效，则调用FormDataService的saveData方法将FormData保存到LocalStorage中。在MyFormComponent的ngOnDestroy方法中，调用FormDataService的clearData方法清除LocalStorage中存储的FormData。