HarmonyOS 文件复制到指定目录的demo

copyFile(fs){
  console.log("copyFile!")
  let context = getContext(this) as common.UIAbilityContext;
  let srcFileDescriptor = context.resourceManager.getRawFdSync('xxx.xx');
  //这里填rawfile文件夹下的文件名（包括后缀）
  let stat = fs.statSync(srcFileDescriptor.fd)
  console.log(`stat isFile:${stat.isFile()}`);
  //通过UIAbilityContext获取沙箱地址filesDir，以Stage模型为例
  let pathDir = context.filesDir;
  console.log("path:",pathDir)
  let dstPath = pathDir + "/xxx.xx";
  let dest = fs.openSync(dstPath, fs.OpenMode.CREATE | fs.OpenMode.READ_WRITE)
  let bufsize = 4096
  let buf = new ArrayBuffer(stat.size)
  let off = 0, len = 0, readedLen = 0
  while (len = fs.readSync(srcFileDescriptor.fd, buf, { offset: srcFileDescriptor.offset + off, length: bufsize })) {
    readedLen += len
    fs.writeSync(dest.fd, buf, { offset: off, length: len })
    off = off + len
    if ((srcFileDescriptor.length - readedLen) < bufsize) {
      bufsize = srcFileDescriptor.length - readedLen
    }
  }
  fs.close(dest.fd)
}