如何在Java中將長度爲給定字符串的UTF-8編碼的字節的MD5散列的前8個字節表示爲長整型？

Question

如何將給定String的UTF-8編碼字節的MD5散列的前8個字節表示爲java中的long？

Answer 1

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)); 
} 

Answer 2

試試這個：

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