HarmonyOS 文件访问（fs）和webview加载本地资源是只支持沙箱路径吗，实际物理路径加载失败

1、出于安全考虑，应用无法直接读取系统路径，加载本地资源仅支持沙箱路径

2、若使用系统公共目录文件，需将文件拷贝至沙箱目录下

沙箱路径：

https://developer.huawei.com/consumer/cn/doc/harmonyos-guides-V5/app-sandbox-directory-V5

Demo：

pickerPhoto() {
  try {
    let options = new picker.PhotoSelectOptions();
    options.MIMEType = picker.PhotoViewMIMETypes.IMAGE_TYPE;
    options.maxSelectNumber = 1;
    let p = new picker.PhotoViewPicker();

    p.select(options).then((res:picker.PhotoSelectResult) => {
      console.info("tag photo is uri" + res.photoUris[0])
      this.saveFile(res.photoUris[0]);
    })
  } catch (e) {
    console.error("tag select tailed..")
  }
}


async saveFile(uri: string) {
  // 将公共目录的文件，拷贝至沙箱路径
  let destDist = getContext(this).cacheDir + "/test.png";

  let src = fs.openSync(uri, fs.OpenMode.READ_ONLY);
  let dst = fs.openSync(destDist, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
  fs.copyFileSync(src.fd, dst.fd);
}