MD5的作用详见:https://baike.baidu.com/item/MD5/212708?fr=aladdin
public static string GetFileMD5(string filepath)
{
FileStream fs = new FileStream(filepath, FileMode.Open, FileAccess.Read, FileShare.Read);
int bufferSize = 1048576;
byte[] buff = new byte[bufferSize];
MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
md5.Initialize();
long offset = 0;
while (offset < fs.Length)
{
long readSize = bufferSize;
if (offset + readSize > fs.Length)
readSize = fs.Length - offset;
fs.Read(buff, 0, Convert.ToInt32(readSize));
if (offset + readSize < fs.Length)
md5.TransformBlock(buff, 0, Convert.ToInt32(readSize), buff, 0);
else
md5.TransformFinalBlock(buff, 0, Convert.ToInt32(readSize));
offset += bufferSize;
}
if (offset >= fs.Length)
{
fs.Close();
byte[] result = md5.Hash;
md5.Clear();
StringBuilder sb = new StringBuilder(32);
for (int i = 0; i < result.Length; i++)
sb.Append(result[i].ToString("X2"));
return sb.ToString();
}
else
{
fs.Close();
return null;
}
}
filepath:文件的绝对路径