如何在Java中將給定String的UTF-8編碼的字節的MD5哈希的前8個字節表示為long？

Question

如何在Java中將給定String的UTF-8編碼的字節的MD5哈希的前8個字節表示為long？

Answer 1

嘗試這個：

MessageDigest md5 = MessageDigest.getInstance("MD5");
byte[] digest = md5.digest("Wallace".getBytes("UTF-8"));
long result = ByteBuffer.wrap(digest).getLong();

Answer 2

public static void main(final String[] args) throws Exception
{
    final MessageDigest md5 = MessageDigest.getInstance("MD5");
    final byte[] digest = md5.digest("Grommit".getBytes("UTF-8"));
    long result = 0;
    for (int i = 0; i < 8; i++)
    {
        System.out.println(Long.toHexString(0xFFL & digest[i]));
        result |= (0xFFL & digest[i]) << (i * 8);
    }
    System.out.println(Long.toHexString(result));
}