如何在GO中计算文件的校验和

I need calculate checksum of a file to determine the integrity of data of existing file. I need it for large files to avoid the download. Can you give me any idea?

You can do that by :

f, err := os.Open(path)
if err != nil {
    glog.Fatal(err)
}
defer f.Close()

hasher := sha256.New()
if _, err := io.Copy(hasher, f); err != nil {
    glog.Fatal(err)
}
value:= hex.EncodeToString(hasher.Sum(nil))