typescript
import dataPreferences from '@ohos.data.preferences';

class PrefsOptimizedUtil {
  private static instance: PrefsOptimizedUtil;
  private prefs: dataPreferences.Preferences | null = null;
  private cache: Record<string, any> = {}; // 内存缓存常用数据

  private constructor() {}

  // 单例初始化，避免重复创建
  public static async getInstance(context: any): Promise<PrefsOptimizedUtil> {
    if (!this.instance) {
      this.instance = new PrefsOptimizedUtil();
      this.instance.prefs = await dataPreferences.getPreferences(context, "app_config");
      // 初始化缓存常用数据
      await this.instance.initCache();
    }
    return this.instance;
  }

  // 初始化缓存
  private async initCache() {
    const keys = ["theme_mode", "music_volume", "login_status"];
    const batchData = await this.prefs?.getBatch(keys); // API 20批量读取
    if (batchData) this.cache = batchData;
  }

  // 读取数据（优先从缓存获取）
  public getData<T>(key: string, defaultValue: T): T {
    return this.cache[key] ?? defaultValue;
  }

  // 批量写入数据，统一flush
  public async batchPutData(data: Record<string, any>) {
    if (!this.prefs) return;
    Object.keys(data).forEach(key => this.cache[key] = data[key]);
    await this.prefs.putBatch(data); // API 20批量写入
    await this.prefs.flush(); // 统一持久化
  }
}