HarmonyOS鸿蒙Next中如何在应用中实现数据备份与恢复？

可以参考这个帖子：https://developer.huawei.com/consumer/cn/forum/topic/0202202005856127136?fid=0109140870620153026

分享了完整的实现方案。
StorageManager：

import { preferences } from '@kit.ArkData'
import { common } from '@kit.AbilityKit'

export class StorageManager {
  private static instance: StorageManager
  private preferences: preferences.Preferences | null = null
  private context: common.UIAbilityContext | null = null
  private readonly STORE_NAME: string = 'math_calculator_store'

  private constructor() {
  }

  static getInstance(): StorageManager {
    if (!StorageManager.instance) {
      StorageManager.instance = new StorageManager()
    }
    return StorageManager.instance
  }

  async init(context: common.UIAbilityContext): Promise<boolean> {
    try {
      this.context = context
      this.preferences = await preferences.getPreferences(context, this.STORE_NAME)
      return true
    } catch (error) {
      console.error(`Storage init failed: ${JSON.stringify(error)}`)
      return false
    }
  }

  async setString(key: string, value: string): Promise<StorageResult<void>> {
    if (!this.preferences) {
      return { success: false, errorMsg: '存储未初始化' }
    }
    try {
      await this.preferences.put(key, value)
      await this.preferences.flush()
      return { success: true }
    } catch (error) {
      return { success: false, errorMsg: `存储失败: ${JSON.stringify(error)}` }
    }
  }

  async getString(key: string, defaultValue: string = ''): Promise<StorageResult<string>> {
    if (!this.preferences) {
      return { success: false, errorMsg: '存储未初始化' }
    }
    try {
      const value = await this.preferences.get(key, defaultValue) as string
      return { success: true, data: value }
    } catch (error) {
      return { success: false, errorMsg: `读取失败: ${JSON.stringify(error)}` }
    }
  }

  async setObject<T>(key: string, value: T): Promise<StorageResult<void>> {
    try {
      const jsonString: string = JSON.stringify(value)
      return await this.setString(key, jsonString)
    } catch (error) {
      return { success: false, errorMsg: `序列化失败: ${JSON.stringify(error)}` }
    }
  }

  async getObject<T>(key: string, defaultValue: T): Promise<StorageResult<T>> {
    try {
      const result = await this.getString(key, '')
      if (!result.success || !result.data) {
        return { success: true, data: defaultValue }
      }
      const parsed: T = JSON.parse(result.data)
      return { success: true, data: parsed }
    } catch (error) {
      return { success: false, errorMsg: `反序列化失败: ${JSON.stringify(error)}` }
    }
  }

  async remove(key: string): Promise<StorageResult<void>> {
    if (!this.preferences) {
      return { success: false, errorMsg: '存储未初始化' }
    }
    try {
      await this.preferences.delete(key)
      await this.preferences.flush()
      return { success: true }
    } catch (error) {
      return { success: false, errorMsg: `删除失败: ${JSON.stringify(error)}` }
    }
  }

  async has(key: string): Promise<boolean> {
    if (!this.preferences) {
      return false
    }
    try {
      return await this.preferences.has(key)
    } catch (error) {
      return false
    }
  }

  async clear(): Promise<StorageResult<void>> {
    if (!this.preferences) {
      return { success: false, errorMsg: '存储未初始化' }
    }
    try {
      await this.preferences.clear()
      await this.preferences.flush()
      return { success: true }
    } catch (error) {
      return { success: false, errorMsg: `清空失败: ${JSON.stringify(error)}` }
    }
  }
}

// 存储结果接口
interface StorageResult<T> {
  success: boolean
  data?: T
  errorMsg?: string
}