求大佬告知如何保存cookie

// xxx.ets 
import { BusinessError } from '@ohos.base'; 
import { preferences } from '@kit.ArkData'; 
import { promptAction } from '@kit.ArkUI'; 
 
@Entry 
@Component 
struct Index { 
  preferences: preferences.Preferences | null = null; 
  @State cookie: string = ''; 
 
  async aboutToAppear() { 
    // 获取Preferences实例 
    this.preferences = await preferences.getPreferences(getContext(this), 'myStore'); 
  } 
 
  putPreference() { 
    // 将数据写入缓存的Preferences实例中 
    this.preferences?.put('cookie', this.cookie); 
    // 通过flush将Preferences实例持久化 
    this.preferences?.flush(); 
  } 
 
  getPreference() { 
    // 从缓存的Preferences实例中获取键对应的值 
    this.preferences?.get('cookie', '', (err: BusinessError, val: preferences.ValueType) => { 
      this.cookie = val.toString(); 
    }) 
  } 
 
  build() { 
    Column({ space: 15 }) { 
      Text(`Cookie：${this.cookie}`) 
        .width('95%') 
      TextInput({ placeholder: '请输入Cookie', text: this.cookie }) 
        .showUnderline(true) 
        .width(380) 
        .onChange((value: string) => { 
          this.cookie = value; 
        }) 
      Button('保存Cookie', { type: ButtonType.Normal, stateEffect: true }) 
        .borderRadius(8) 
        .backgroundColor(0x317aff) 
        .width(90) 
        .onClick(() => { 
          this.putPreference(); 
        }) 
      Button('读取Cookie', { type: ButtonType.Normal, stateEffect: true }) 
        .borderRadius(8) 
        .backgroundColor(0x317aff) 
        .width(90) 
        .onClick(() => { 
          this.getPreference(); 
        }) 
    } 
  } 
}