HarmonyOS APP开发中常用到的分布式数据迁移

换新手机了，数据怎么办？一条条手动迁移？太痛苦了。设备切换数据迁移，让"换机"从噩梦变享受，一键搞定所有数据。

一、为什么需要设备切换迁移？

1.1 设备切换的痛点

换机场景：

• 旧手机 → 新手机
• 手机 → 平板
• 平板 → 智慧屏

传统方式的痛苦：

• 耗时：手动迁移动辄几小时
• 遗漏：总有些数据忘记迁移
• 混乱：数据重复、版本混乱
• 风险：迁移过程数据丢失

1.2 迁移的价值

设备切换迁移让数据"无缝搬家"：

二、核心原理：迁移机制详解

2.1 迁移类型

HarmonyOS支持多种迁移类型：

本地迁移：

• 两设备直接连接
• 通过WiFi Direct、蓝牙等传输
• 速度快，无需网络

云端迁移：

• 通过云端中转
• 不限距离
• 需要网络，速度受限于带宽

混合迁移：

• 结合本地和云端
• 智能选择最优路径
• 大文件本地，小文件云端

2.2 迁移数据分类

不同类型的数据采用不同的迁移策略：

enum MigrationDataType {
  // 应用数据
  APP_DATA = 'app_data',           // 应用数据库、配置等
  
  // 用户数据
  USER_DATA = 'user_data',         // 用户文档、照片等
  
  // 系统设置
  SYSTEM_SETTINGS = 'system_settings',  // 主题、字体、语言等
  
  // 账号信息
  ACCOUNT_INFO = 'account_info',   // 登录状态、账号数据
  
  // 媒体文件
  MEDIA_FILES = 'media_files',     // 照片、视频、音频
  
  // 缓存数据
  CACHE_DATA = 'cache_data'        // 不迁移或选择性迁移
}

2.3 迁移流程

三、代码实战：实现设备切换迁移

3.1 基础示例：数据迁移

import distributedData from '@ohos.data.distributedData';
import deviceManager from '@ohos.distributedDeviceManager';
import { BusinessError } from '@ohos.base';

/**
 * 数据迁移管理器
 * 提供设备间的数据迁移能力
 */
export class DataMigrationManager {
  private kvStore: distributedData.KVStore | null = null;
  private deviceManager: deviceManager.DeviceManager | null = null;
  
  /**
   * 初始化
   */
  async init(): Promise<void> {
    try {
      // 初始化KV存储
      const kvManager = distributedData.createKVManager({
        bundleName: 'com.example.myapp',
        userId: 0
      });
      
      this.kvStore = await kvManager.getKVStore('migration_store', {
        createIfMissing: true,
        autoSync: false,  // 迁移时禁用自动同步
        kvStoreType: distributedData.KVStoreType.DEVICE_COLLABORATION,
        securityLevel: distributedData.SecurityLevel.S2
      });
      
      // 初始化设备管理器
      this.deviceManager = deviceManager.createDeviceManager('com.example.myapp');
      
      console.info('[DataMigration] 初始化成功');
    } catch (error) {
      const err = error as BusinessError;
      console.error(`[DataMigration] 初始化失败: ${err.message}`);
      throw error;
    }
  }
  
  /**
   * 准备迁移
   * 扫描并分类待迁移数据
   */
  async prepareMigration(): Promise<MigrationPlan> {
    if (!this.kvStore) {
      throw new Error('KV存储未初始化');
    }
    
    try {
      console.info('[DataMigration] 开始准备迁移');
      
      // 获取所有数据键
      const allKeys = await this.kvStore.getAllKeys();
      
      // 分类数据
      const categories = await this.categorizeData(allKeys);
      
      // 计算数据大小
      const sizes = await this.calculateSizes(categories);
      
      // 构造迁移计划
      const plan: MigrationPlan = {
        totalItems: allKeys.length,
        totalSize: Object.values(sizes).reduce((a, b) => a + b, 0),
        categories: categories,
        sizes: sizes,
        estimatedTime: this.estimateTime(Object.values(sizes).reduce((a, b) => a + b, 0))
      };
      
      console.info(`[DataMigration] 迁移准备完成: ${plan.totalItems} 项, ${this.formatSize(plan.totalSize)}`);
      
      return plan;
    } catch (error) {
      console.error(`[DataMigration] 准备迁移失败: ${error}`);
      throw error;
    }
  }
  
  /**
   * 执行迁移
   * @param targetDeviceId 目标设备ID
   * @param plan 迁移计划
   * @param options 迁移选项
   */
  async executeMigration(targetDeviceId: string, plan: MigrationPlan, 
                        options: MigrationOptions): Promise<MigrationResult> {
    const result: MigrationResult = {
      success: false,
      migratedItems: 0,
      migratedSize: 0,
      errors: [],
      startTime: Date.now()
    };
    
    try {
      console.info(`[DataMigration] 开始迁移到设备: ${targetDeviceId}`);
      
      // 检查目标设备
      const deviceAvailable = await this.checkDevice(targetDeviceId);
      if (!deviceAvailable) {
        throw new Error('目标设备不可用');
      }
      
      // 建立迁移通道
      const channel = await this.establishChannel(targetDeviceId);
      
      // 按类别迁移数据
      for (const [category, keys] of Object.entries(plan.categories)) {
        // 检查是否需要迁移该类别
        if (!options.categories.includes(category as MigrationDataType)) {
          continue;
        }
        
        console.info(`[DataMigration] 迁移类别: ${category}, ${keys.length} 项`);
        
        // 批量迁移
        const batchResult = await this.migrateBatch(channel, keys, options);
        
        result.migratedItems += batchResult.migratedItems;
        result.migratedSize += batchResult.migratedSize;
        result.errors.push(...batchResult.errors);
      }
      
      // 关闭迁移通道
      await this.closeChannel(channel);
      
      result.success = result.errors.length === 0;
      result.endTime = Date.now();
      result.duration = result.endTime - result.startTime;
      
      console.info(`[DataMigration] 迁移完成: ${result.migratedItems} 项, 耗时 ${result.duration}ms`);
      
    } catch (error) {
      result.errors.push(String(error));
      console.error(`[DataMigration] 迁移失败: ${error}`);
    }
    
    return result;
  }
  
  /**
   * 接收迁移数据
   * 在新设备上执行
   */
  async receiveMigration(sourceDeviceId: string, options: ReceiveOptions): Promise<ReceiveResult> {
    const result: ReceiveResult = {
      success: false,
      receivedItems: 0,
      appliedItems: 0,
      errors: []
    };
    
    try {
      console.info(`[DataMigration] 开始接收来自设备的数据: ${sourceDeviceId}`);
      
      // 建立接收通道
      const channel = await this.establishReceiveChannel(sourceDeviceId);
      
      // 接收数据清单
      const manifest = await this.receiveManifest(channel);
      
      // 用户确认
      const confirmed = await this.confirmMigration(manifest, options);
      if (!confirmed) {
        console.info('[DataMigration] 用户取消迁移');
        return result;
      }
      
      // 接收数据
      const receivedData = await this.receiveData(channel, manifest, (progress) => {
        console.info(`[DataMigration] 接收进度: ${progress.percentage}%`);
      });
      
      result.receivedItems = receivedData.size;
      
      // 应用数据
      await this.applyMigratedData(receivedData, options.mergeStrategy);
      
      result.appliedItems = receivedData.size;
      result.success = true;
      
      console.info(`[DataMigration] 接收完成: ${result.appliedItems} 项`);
      
    } catch (error) {
      result.errors.push(String(error));
      console.error(`[DataMigration] 接收失败: ${error}`);
    }
    
    return result;
  }
  
  /**
   * 分类数据
   */
  private async categorizeData(keys: string[]): Promise<Record<string, string[]>> {
    const categories: Record<string, string[]> = {
      [MigrationDataType.APP_DATA]: [],
      [MigrationDataType.USER_DATA]: [],
      [MigrationDataType.SYSTEM_SETTINGS]: [],
      [MigrationDataType.ACCOUNT_INFO]: [],
      [MigrationDataType.MEDIA_FILES]: [],
      [MigrationDataType.CACHE_DATA]: []
    };
    
    for (const key of keys) {
      const category = this.detectCategory(key);
      categories[category].push(key);
    }
    
    return categories;
  }
  
  /**
   * 检测数据类别
   */
  private detectCategory(key: string): string {
    // 根据key前缀判断类别
    if (key.startsWith('app_')) {
      return MigrationDataType.APP_DATA;
    } else if (key.startsWith('user_')) {
      return MigrationDataType.USER_DATA;
    } else if (key.startsWith('setting_')) {
      return MigrationDataType.SYSTEM_SETTINGS;
    } else if (key.startsWith('account_')) {
      return MigrationDataType.ACCOUNT_INFO;
    } else if (key.startsWith('media_')) {
      return MigrationDataType.MEDIA_FILES;
    } else {
      return MigrationDataType.CACHE_DATA;
    }
  }
  
  /**
   * 计算各类数据大小
   */
  private async calculateSizes(categories: Record<string, string[]>): Promise<Record<string, number>> {
    const sizes: Record<string, number> = {};
    
    for (const [category, keys] of Object.entries(categories)) {
      let size = 0;
      for (const key of keys) {
        const value = await this.kvStore!.get(key);
        size += this.estimateSize(value);
      }
      sizes[category] = size;
    }
    
    return sizes;
  }
  
  /**
   * 估算数据大小
   */
  private estimateSize(value: any): number {
    if (typeof value === 'string') {
      return value.length * 2;  // UTF-16
    } else if (value instanceof ArrayBuffer) {
      return value.byteLength;
    } else {
      return JSON.stringify(value).length * 2;
    }
  }
  
  /**
   * 估算迁移时间
   */
  private estimateTime(totalSize: number): number {
    // 假设传输速度为10MB/s
    const speed = 10 * 1024 * 1024;
    return Math.ceil(totalSize / speed * 1000);  // 毫秒
  }
  
  /**
   * 批量迁移数据
   */
  private async migrateBatch(channel: MigrationChannel, keys: string[], 
                            options: MigrationOptions): Promise<BatchMigrationResult> {
    const result: BatchMigrationResult = {
      migratedItems: 0,
      migratedSize: 0,
      errors: []
    };
    
    const batchSize = options.batchSize || 100;
    
    for (let i = 0; i < keys.length; i += batchSize) {
      const batch = keys.slice(i, i + batchSize);
      
      try {
        // 读取数据
        const data = new Map<string, any>();
        for (const key of batch) {
          const value = await this.kvStore!.get(key);
          data.set(key, value);
        }
        
        // 发送数据
        await this.sendData(channel, data);
        
        result.migratedItems += batch.length;
        result.migratedSize += Array.from(data.values())
          .reduce((sum, v) => sum + this.estimateSize(v), 0);
        
      } catch (error) {
        result.errors.push(`批次 ${i / batchSize} 失败: ${error}`);
      }
    }
    
    return result;
  }
  
  /**
   * 检查设备可用性
   */
  private async checkDevice(deviceId: string): Promise<boolean> {
    if (!this.deviceManager) return false;
    
    try {
      const deviceInfo = await this.deviceManager.getDeviceInfo(deviceId);
      return deviceInfo.state === deviceManager.DeviceState.ONLINE;
    } catch {
      return false;
    }
  }
  
  /**
   * 建立迁移通道
   */
  private async establishChannel(deviceId: string): Promise<MigrationChannel> {
    // 实际项目中建立设备间通信通道
    return { deviceId, connected: true };
  }
  
  /**
   * 关闭迁移通道
   */
  private async closeChannel(channel: MigrationChannel): Promise<void> {
    channel.connected = false;
  }
  
  /**
   * 发送数据
   */
  private async sendData(channel: MigrationChannel, data: Map<string, any>): Promise<void> {
    // 实际发送逻辑
  }
  
  /**
   * 建立接收通道
   */
  private async establishReceiveChannel(deviceId: string): Promise<MigrationChannel> {
    return { deviceId, connected: true };
  }
  
  /**
   * 接收数据清单
   */
  private async receiveManifest(channel: MigrationChannel): Promise<MigrationManifest> {
    return { items: [], totalSize: 0 };
  }
  
  /**
   * 确认迁移
   */
  private async confirmMigration(manifest: MigrationManifest, options: ReceiveOptions): Promise<boolean> {
    return options.autoConfirm || true;
  }
  
  /**
   * 接收数据
   */
  private async receiveData(channel: MigrationChannel, manifest: MigrationManifest,
                           onProgress: (progress: Progress) => void): Promise<Map<string, any>> {
    return new Map();
  }
  
  /**
   * 应用迁移数据
   */
  private async applyMigratedData(data: Map<string, any>, strategy: MergeStrategy): Promise<void> {
    for (const [key, value] of data) {
      if (strategy === 'overwrite') {
        await this.kvStore!.put(key, value);
      } else if (strategy === 'merge') {
        // 合并策略：保留新数据
        try {
          const existing = await this.kvStore!.get(key);
          // 比较时间戳，保留新的
          // 这里简化处理
          await this.kvStore!.put(key, value);
        } catch {
          await this.kvStore!.put(key, value);
        }
      }
    }
  }
  
  /**
   * 格式化大小
   */
  private formatSize(bytes: number): string {
    if (bytes < 1024) return `${bytes} B`;
    if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(2)} KB`;
    if (bytes < 1024 * 1024 * 1024) return `${(bytes / (1024 * 1024)).toFixed(2)} MB`;
    return `${(bytes / (1024 * 1024 * 1024)).toFixed(2)} GB`;
  }
}

interface MigrationPlan {
  totalItems: number;
  totalSize: number;
  categories: Record<string, string[]>;
  sizes: Record<string, number>;
  estimatedTime: number;
}

interface MigrationOptions {
  categories: MigrationDataType[];
  batchSize?: number;
  compress?: boolean;
  encrypt?: boolean;
}

interface MigrationResult {
  success: boolean;
  migratedItems: number;
  migratedSize: number;
  errors: string[];
  startTime: number;
  endTime?: number;
  duration?: number;
}

interface ReceiveOptions {
  autoConfirm?: boolean;
  mergeStrategy: 'overwrite' | 'merge' | 'skip';
}

interface ReceiveResult {
  success: boolean;
  receivedItems: number;
  appliedItems: number;
  errors: string[];
}

interface MigrationChannel {
  deviceId: string;
  connected: boolean;
}

interface BatchMigrationResult {
  migratedItems: number;
  migratedSize: number;
  errors: string[];
}

interface MigrationManifest {
  items: string[];
  totalSize: number;
}

interface Progress {
  percentage: number;
  transferred: number;
  total: number;
}

type MergeStrategy = 'overwrite' | 'merge' | 'skip';

3.2 进阶示例：增量迁移

/**
 * 增量迁移管理器
 * 只迁移变更的数据
 */
export class IncrementalMigrationManager extends DataMigrationManager {
  private lastMigrationTime: number = 0;
  
  /**
   * 准备增量迁移
   * 只包含上次迁移后的变更
   */
  async prepareIncrementalMigration(lastMigrationId: string): Promise<MigrationPlan> {
    // 获取上次迁移的时间
    const lastMigration = await this.getMigrationRecord(lastMigrationId);
    this.lastMigrationTime = lastMigration?.timestamp || 0;
    
    // 获取所有数据键
    const allKeys = await this.kvStore!.getAllKeys();
    
    // 过滤出变更的数据
    const changedKeys: string[] = [];
    
    for (const key of allKeys) {
      const metadata = await this.getDataMetadata(key);
      if (metadata.modifyTime > this.lastMigrationTime) {
        changedKeys.push(key);
      }
    }
    
    // 分类变更数据
    const categories = await this.categorizeData(changedKeys);
    
    // 计算大小
    const sizes = await this.calculateSizes(categories);
    
    const plan: MigrationPlan = {
      totalItems: changedKeys.length,
      totalSize: Object.values(sizes).reduce((a, b) => a + b, 0),
      categories,
      sizes,
      estimatedTime: this.estimateTime(Object.values(sizes).reduce((a, b) => a + b, 0))
    };
    
    console.info(`[IncrementalMigration] 增量迁移: ${plan.totalItems} 项变更`);
    
    return plan;
  }
  
  /**
   * 获取数据元数据
   */
  private async getDataMetadata(key: string): Promise<{ modifyTime: number }> {
    // 实际项目中从数据中提取元数据
    return { modifyTime: Date.now() };
  }
  
  /**
   * 获取迁移记录
   */
  private async getMigrationRecord(migrationId: string): Promise<{ timestamp: number } | null> {
    // 从存储中读取迁移记录
    return { timestamp: 0 };
  }
}

3.3 高级示例：选择性迁移与冲突处理

/**
 * 选择性迁移配置
 */
interface SelectiveMigrationConfig {
  // 数据选择规则
  includeRules: MigrationRule[];
  excludeRules: MigrationRule[];
  
  // 冲突处理策略
  conflictStrategy: ConflictStrategy;
  
  // 迁移后操作
  postMigration: PostMigrationAction[];
}

interface MigrationRule {
  type: 'prefix' | 'pattern' | 'category' | 'custom';
  value: string;
  predicate?: (key: string) => boolean;
}

interface ConflictStrategy {
  // 冲突时的默认策略
  default: 'source' | 'target' | 'newer' | 'merge' | 'ask';
  
  // 特定key的策略
  overrides?: Map<string, 'source' | 'target' | 'newer' | 'merge' | 'ask'>;
}

interface PostMigrationAction {
  type: 'delete' | 'archive' | 'notify';
  target: 'source' | 'target';
  keys?: string[];
}

/**
 * 高级迁移管理器
 * 支持选择性迁移和冲突处理
 */
export class AdvancedMigrationManager extends DataMigrationManager {
  /**
   * 选择性迁移
   */
  async selectiveMigration(targetDeviceId: string, config: SelectiveMigrationConfig): Promise<MigrationResult> {
    // 获取所有数据
    const allKeys = await this.kvStore!.getAllKeys();
    
    // 应用包含规则
    let selectedKeys = this.applyIncludeRules(allKeys, config.includeRules);
    
    // 应用排除规则
    selectedKeys = this.applyExcludeRules(selectedKeys, config.excludeRules);
    
    console.info(`[SelectiveMigration] 选择 ${selectedKeys.length} 项数据进行迁移`);
    
    // 执行迁移
    const plan: MigrationPlan = {
      totalItems: selectedKeys.length,
      totalSize: 0,
      categories: { [MigrationDataType.USER_DATA]: selectedKeys },
      sizes: {},
      estimatedTime: 0
    };
    
    return this.executeMigration(targetDeviceId, plan, {
      categories: [MigrationDataType.USER_DATA]
    });
  }
  
  /**
   * 应用包含规则
   */
  private applyIncludeRules(keys: string[], rules: MigrationRule[]): string[] {
    if (rules.length === 0) {
      return keys;  // 无规则，包含所有
    }
    
    const result: Set<string> = new Set();
    
    for (const rule of rules) {
      switch (rule.type) {
        case 'prefix':
          keys.filter(k => k.startsWith(rule.value)).forEach(k => result.add(k));
          break;
          
        case 'pattern':
          const regex = new RegExp(rule.value);
          keys.filter(k => regex.test(k)).forEach(k => result.add(k));
          break;
          
        case 'category':
          keys.filter(k => this.detectCategory(k) === rule.value).forEach(k => result.add(k));
          break;
          
        case 'custom':
          if (rule.predicate) {
            keys.filter(rule.predicate).forEach(k => result.add(k));
          }
          break;
      }
    }
    
    return Array.from(result);
  }
  
  /**
   * 应用排除规则
   */
  private applyExcludeRules(keys: string[], rules: MigrationRule[]): string[] {
    if (rules.length === 0) {
      return keys;
    }
    
    const excludeSet: Set<string> = new Set();
    
    for (const rule of rules) {
      switch (rule.type) {
        case 'prefix':
          keys.filter(k => k.startsWith(rule.value)).forEach(k => excludeSet.add(k));
          break;
          
        case 'pattern':
          const regex = new RegExp(rule.value);
          keys.filter(k => regex.test(k)).forEach(k => excludeSet.add(k));
          break;
          
        case 'category':
          keys.filter(k => this.detectCategory(k) === rule.value).forEach(k => excludeSet.add(k));
          break;
          
        case 'custom':
          if (rule.predicate) {
            keys.filter(rule.predicate).forEach(k => excludeSet.add(k));
          }
          break;
      }
    }
    
    return keys.filter(k => !excludeSet.has(k));
  }
  
  /**
   * 处理迁移冲突
   */
  async handleConflict(sourceData: any, targetData: any, key: string,
                       strategy: ConflictStrategy): Promise<any> {
    // 获取该key的策略
    const keyStrategy = strategy.overrides?.get(key) || strategy.default;
    
    switch (keyStrategy) {
      case 'source':
        return sourceData;
        
      case 'target':
        return targetData;
        
      case 'newer':
        const sourceTime = this.extractTimestamp(sourceData);
        const targetTime = this.extractTimestamp(targetData);
        return sourceTime > targetTime ? sourceData : targetData;
        
      case 'merge':
        return this.mergeData(sourceData, targetData);
        
      case 'ask':
        // 需要用户介入，这里返回null表示需要询问
        return null;
        
      default:
        return sourceData;
    }
  }
  
  /**
   * 合并数据
   */
  private mergeData(source: any, target: any): any {
    // 简单合并：如果是对象，合并字段
    if (typeof source === 'object' && typeof target === 'object') {
      return { ...target, ...source };
    }
    
    // 否则返回源数据
    return source;
  }
  
  /**
   * 提取时间戳
   */
  private extractTimestamp(data: any): number {
    if (typeof data === 'object' && data.timestamp) {
      return data.timestamp;
    }
    return 0;
  }
  
  /**
   * 执行迁移后操作
   */
  async executePostMigration(actions: PostMigrationAction[]): Promise<void> {
    for (const action of actions) {
      switch (action.type) {
        case 'delete':
          if (action.keys) {
            for (const key of action.keys) {
              await this.kvStore!.delete(key);
            }
          }
          break;
          
        case 'archive':
          // 归档数据
          break;
          
        case 'notify':
          // 发送通知
          break;
      }
    }
  }
}

四、踩坑与注意事项

4.1 大数据迁移超时

问题：数据量过大，迁移超时失败。

解决方案：断点续传 + 进度保存

/**
 * 断点续传迁移
 */
export class ResumableMigration extends DataMigrationManager {
  private progressFile: string = '/data/migration_progress.json';
  
  /**
   * 断点续传迁移
   */
  async resumableMigration(targetDeviceId: string): Promise<MigrationResult> {
    // 加载进度
    const progress = await this.loadProgress();
    
    if (progress.completed) {
      console.info('[ResumableMigration] 迁移已完成');
      return { success: true, migratedItems: progress.migratedItems, migratedSize: progress.migratedSize, errors: [], startTime: 0 };
    }
    
    // 从断点继续
    const plan = await this.prepareMigration();
    const remainingKeys = plan.categories[MigrationDataType.USER_DATA]
      .slice(progress.lastIndex);
    
    console.info(`[ResumableMigration] 从第 ${progress.lastIndex} 项继续迁移`);
    
    // 执行迁移...
    
    return { success: true, migratedItems: 0, migratedSize: 0, errors: [], startTime: 0 };
  }
  
  /**
   * 加载进度
   */
  private async loadProgress(): Promise<MigrationProgress> {
    try {
      const data = fs.readTextSync(this.progressFile);
      return JSON.parse(data);
    } catch {
      return { lastIndex: 0, migratedItems: 0, migratedSize: 0, completed: false };
    }
  }
  
  /**
   * 保存进度
   */
  private async saveProgress(progress: MigrationProgress): Promise<void> {
    fs.writeTextSync(this.progressFile, JSON.stringify(progress));
  }
}

interface MigrationProgress {
  lastIndex: number;
  migratedItems: number;
  migratedSize: number;
  completed: boolean;
}

4.2 数据版本不兼容

问题：新旧设备应用版本不同，数据结构不兼容。

解决方案：版本检测 + 数据转换

/**
 * 版本兼容迁移
 */
export class VersionCompatibleMigration extends DataMigrationManager {
  /**
   * 迁移前检查版本兼容性
   */
  async checkCompatibility(targetDeviceId: string): Promise<CompatibilityResult> {
    // 获取本地版本
    const localVersion = await this.getAppVersion();
    
    // 获取目标设备版本
    const targetVersion = await this.getTargetAppVersion(targetDeviceId);
    
    // 比较版本
    if (localVersion === targetVersion) {
      return { compatible: true, needConversion: false };
    }
    
    // 检查是否需要转换
    const needConversion = await this.checkNeedConversion(localVersion, targetVersion);
    
    return { compatible: true, needConversion, localVersion, targetVersion };
  }
  
  /**
   * 转换数据格式
   */
  async convertData(data: Map<string, any>, fromVersion: string, 
                   toVersion: string): Promise<Map<string, any>> {
    const converted = new Map<string, any>();
    
    for (const [key, value] of data) {
      const convertedValue = await this.convertValue(key, value, fromVersion, toVersion);
      converted.set(key, convertedValue);
    }
    
    return converted;
  }
  
  /**
   * 转换单个值
   */
  private async convertValue(key: string, value: any, fromVersion: string, 
                            toVersion: string): Promise<any> {
    // 根据版本差异执行转换
    // 这里简化处理
    return value;
  }
  
  private async getAppVersion(): Promise<string> {
    return '1.0.0';
  }
  
  private async getTargetAppVersion(deviceId: string): Promise<string> {
    return '1.0.0';
  }
  
  private async checkNeedConversion(v1: string, v2: string): Promise<boolean> {
    return v1 !== v2;
  }
}

interface CompatibilityResult {
  compatible: boolean;
  needConversion: boolean;
  localVersion?: string;
  targetVersion?: string;
}

4.3 迁移中断处理

问题：迁移过程中断，数据状态不一致。

解决方案：事务性迁移 + 回滚机制

/**
 * 事务性迁移
 */
export class TransactionalMigration extends DataMigrationManager {
  /**
   * 事务性迁移
   */
  async transactionalMigration(targetDeviceId: string): Promise<MigrationResult> {
    // 开始事务
    const transaction = await this.beginTransaction();
    
    try {
      // 备份目标设备当前数据
      await this.backupTargetData(targetDeviceId, transaction);
      
      // 执行迁移
      const result = await this.executeMigration(targetDeviceId, await this.prepareMigration(), {
        categories: [MigrationDataType.USER_DATA]
      });
      
      if (!result.success) {
        // 迁移失败，回滚
        await this.rollback(transaction);
        return result;
      }
      
      // 提交事务
      await this.commit(transaction);
      
      return result;
      
    } catch (error) {
      // 异常，回滚
      await this.rollback(transaction);
      throw error;
    }
  }
  
  /**
   * 开始事务
   */
  private async beginTransaction(): Promise<MigrationTransaction> {
    return {
      id: 'txn_' + Date.now(),
      startTime: Date.now(),
      status: 'active'
    };
  }
  
  /**
   * 备份目标数据
   */
  private async backupTargetData(deviceId: string, transaction: MigrationTransaction): Promise<void> {
    // 备份目标设备的当前数据，用于回滚
  }
  
  /**
   * 提交事务
   */
  private async commit(transaction: MigrationTransaction): Promise<void> {
    transaction.status = 'committed';
    // 清理备份数据
  }
  
  /**
   * 回滚事务
   */
  private async rollback(transaction: MigrationTransaction): Promise<void> {
    transaction.status = 'rolledback';
    // 恢复备份数据
  }
}

interface MigrationTransaction {
  id: string;
  startTime: number;
  status: 'active' | 'committed' | 'rolledback';
}

五、HarmonyOS 6适配指南

5.1 API变更

5.1.1 迁移API增强

// HarmonyOS 6新增：一键迁移
import migration from '@kit.Migration';

const migrationManager = migration.getMigrationManager();

// 一键迁移
await migrationManager.migrate({
  targetDeviceId: 'device_xxx',
  
  // 数据选择
  dataTypes: [
    migration.DataType.APP_DATA,
    migration.DataType.USER_DATA,
    migration.DataType.SYSTEM_SETTINGS
  ],
  
  // 冲突策略
  conflictStrategy: 'newer',
  
  // 迁移模式
  mode: 'local',  // 或 'cloud' 或 'hybrid'
  
  // 进度回调
  onProgress: (progress) => {
    console.info(`迁移进度: ${progress.percentage}%`);
  }
});

5.2 性能优化

/**
 * HarmonyOS 6迁移性能优化
 */
export class HarmonyOS6MigrationOptimization {
  /**
   * 推荐配置
   */
  getOptimizedOptions(): MigrationOptions {
    return {
      categories: [
        MigrationDataType.APP_DATA,
        MigrationDataType.USER_DATA,
        MigrationDataType.SYSTEM_SETTINGS,
        MigrationDataType.ACCOUNT_INFO
      ],
      batchSize: 500,
      compress: true,
      encrypt: true
    };
  }
}

六、总结一下下

设备切换迁移是提升用户体验的关键能力。通过本文的深度解析，我们掌握了：

核心要点：

1. 迁移类型：本地迁移、云端迁移、混合迁移
2. 数据分类：应用数据、用户数据、系统设置、账号信息等
3. 迁移流程：准备→传输→应用→确认
4. 增量迁移：只迁移变更数据，提升效率
5. 选择性迁移：按规则筛选数据，灵活控制
6. 冲突处理：多种策略解决数据冲突

最佳实践：

• 大数据：分批迁移，断点续传
• 版本差异：检测兼容性，转换数据格式
• 关键数据：事务性迁移，支持回滚
• 增量迁移：定期执行，保持数据同步

迁移策略建议：

迁移场景
├─ 换新设备
│  ├─ 全量迁移
│  └─ 保留旧设备数据
├─ 设备同步
│  ├─ 增量迁移
│  └─ 双向同步
└─ 数据恢复
   ├─ 云端恢复
   └─ 合并现有数据

掌握设备切换迁移，让用户告别换机烦恼，享受无缝的数据体验。