HarmonyOS如何对一个文件内容进行MD5计算

/** 
 * 获取单个文件的MD5值 
 */ 
public static async getFileMD5(filePath: string): Promise<string> { 
  let fState: fs.Stat = fs.statSync(filePath); 
  if (!fState.isFile()) { 
  return ""; 
} 
let file = fs.openSync(filePath, fs.OpenMode.READ_ONLY); 
try { 
  let md = cryptoFramework.createMd('MD5'); 
  let arrayBuffer = new ArrayBuffer(1024); 
  let offset = 0; 
  let readLen = -1; 
  do { 
    readLen = fs.readSync(file.fd, arrayBuffer, { 
      offset: offset,// 表示期望读取文件的位置。可选，默认从当前位置开始读。 
      length: 1024 // 表示期望读取数据的长度。可选，默认缓冲区长度。 
    }) 
    if (readLen > 0) { 
      offset += readLen; 
      let buf = buffer.from(arrayBuffer, 0, readLen).buffer; 
      let updateMessageBlob: cryptoFramework.DataBlob = { data: new Uint8Array(buf) }; 
      await md.update(updateMessageBlob); 
    } 
  } while (readLen > 0) 
  let mdOutput = await md.digest(); 
  return StringUtils.uint8ArrayToHexStr(mdOutput.data); 
} catch (e) { 
  return ""; 
} finally { 
  fs.closeSync(file); 
} 
}