如何获取preference中缓存的值？

/**
 * 获取缓存值
 * @param key
 * @param defValue
 * @returns
 */
static getSync(key: string, defValue: preferences.ValueType): preferences.ValueType {
  let preferences = PreferencesUtil.getPreferencesSync(); //获取实例
  return preferences.getSync(key, defValue);
}