Java Convert via ByteBuffer toGuidString(UUID uuid)

Description

to Guid String

License

Open Source License

Declaration

public static String toGuidString(UUID uuid) 

Method Source Code

//package com.java2s;
//  License: https://servicestack.net/bsd-license.txt

import java.nio.ByteBuffer;

import java.util.UUID;

public class Main {
    final protected static char[] hexArray = "0123456789ABCDEF".toCharArray();

    public static String toGuidString(UUID uuid) {
        byte[] guidBytes = toGuidBytes(uuid);
        String to = toHex(guidBytes);
        return to;
    }//from  www.j  a v  a2s.c o  m

    public static byte[] toGuidBytes(UUID theUuid) {
        ByteBuffer first8 = ByteBuffer.allocate(8);
        first8.putLong(theUuid.getMostSignificantBits());
        first8.rewind();

        byte[] first4 = new byte[4];
        first8.get(first4);
        reverse(first4);

        byte[] second2 = new byte[2];
        first8.get(second2);
        reverse(second2);

        byte[] third2 = new byte[2];
        first8.get(third2);
        reverse(third2);

        ByteBuffer converted16 = ByteBuffer.allocate(16).put(first4).put(second2).put(third2);

        ByteBuffer last8 = ByteBuffer.allocate(8);
        last8.putLong(theUuid.getLeastSignificantBits());
        last8.rewind();

        converted16.put(last8);

        return converted16.array();
    }

    public static String toHex(byte[] bytes) {
        char[] hexChars = new char[bytes.length * 2];
        for (int j = 0; j < bytes.length; j++) {
            int v = bytes[j] & 0xFF;
            hexChars[j * 2] = hexArray[v >>> 4];
            hexChars[j * 2 + 1] = hexArray[v & 0x0F];
        }
        return new String(hexChars);
    }

    public static void reverse(byte[] bytes) {
        if (bytes == null)
            return;

        int i = 0;
        int j = bytes.length - 1;
        byte hold;
        while (j > i) {
            hold = bytes[j];
            bytes[j] = bytes[i];
            bytes[i] = hold;
            j--;
            i++;
        }
    }
}

Related

1. toFloat(byte[] bytes)
2. toFloat(final byte[] b)
3. toFloatArray(int[] intArray)
4. toFloatBytes(List datas)
5. toGuidBytes(UUID theUuid)
6. toHex(byte[] bytes)
7. toHexBytes(byte[] bytes)
8. toHexString(Number n)
9. toInt(byte[] bytes)