How: convert byte[] to hex encoded string

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gauravs_mailbox@yahoo.com - 25 Sep 2006 12:20 GMT

Hi All,

I want to covert the byte to hex encoded string.

Any pointers how to do that , would be really appreciated.

Regards,
Gaurav

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Thomas Kellerer - 25 Sep 2006 12:23 GMT

gauravs_mailbox@yahoo.com wrote on 25.09.2006 13:20:

> Hi All,
>
> I want to covert the byte to hex encoded string.
>
> Any pointers how to do that , would be really appreciated.

Loop over the bytes and use Integer.toHexString()

Thomas

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gauravs_mailbox@yahoo.com - 25 Sep 2006 13:46 GMT

> gauravs_mailbox@yahoo.com wrote on 25.09.2006 13:20:
> > Hi All,
[quoted text clipped - 6 lines]
>
> Thomas

Hi Thomas,

thnx for your reply..

But I want to make sure that my string is exactly 20 bytes long and if
its not , i need to pad it up .. any tips ?

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Thomas Kellerer - 25 Sep 2006 13:57 GMT

gauravs_mailbox@yahoo.com wrote on 25.09.2006 14:46:

>> gauravs_mailbox@yahoo.com wrote on 25.09.2006 13:20:
>>> Hi All,
[quoted text clipped - 12 lines]
> But I want to make sure that my string is exactly 20 bytes long and if
> its not , i need to pad it up .. any tips ?

Then you will need to check the length of your byte array and the length of the
resulting string. Where is the problem?

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Thomas Schodt - 25 Sep 2006 15:57 GMT

> I want to convert the byte array to hex encoded string.
>
> Any pointers how to do that , would be really appreciated.

<http://www.websina.com/products/license/com/websina/util/ByteHex.html>

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Red Orchid - 25 Sep 2006 16:02 GMT

gauravs_mailbox@yahoo.com wrote or quoted in
Message-ID: <1159183251.406057.71460@e3g2000cwe.googlegroups.com>:

> I want to covert the byte to hex encoded string.

This is one example.

<code>
// not tested.

protected static final byte[] Hexhars = {

'0', '1', '2', '3', '4', '5',
'6', '7', '8', '9', 'a', 'b',
'c', 'd', 'e', 'f'
};

public static String encode(byte[] b) {

StringBuilder s = new StringBuilder(2 * b.length);

for (int i = 0; i < b.length; i++) {

int v = b[i] & 0xff;

s.append((char)Hexhars[v >> 4]);
s.append((char)Hexhars[v & 0xf]);
}

return s.toString();
}

</code>

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Mark Space - 26 Sep 2006 23:36 GMT

> Hi All,
>
[quoted text clipped - 4 lines]
> Regards,
> Gaurav

Another thought:

static void loadFile (JFrameFileLoader jfl, File f)
{
    JTextArea jta = jfl.getTextArea();

if (f != null)
{
    jfl.setFilename( f.getName () );
    jta.setText ( "" );
    FileChannel fc;
    try
    {
        fc = new FileInputStream (f).getChannel();
    } catch (FileNotFoundException ex)
    {
        jta.setText ("File not found.");
        return;
    }

    MappedByteBuffer mmf;
    try
    {
        mmf = fc.map(FileChannel.MapMode.READ_ONLY, 0, fc.size());
    } catch (IOException ex)
    {
        jta.setText ("Error opening file.");
        return;
    }
    try
    {
        for (long i=0; i < fc.size(); i+=16)
        {
        jta.append ( myToHexString(i,8) );
        jta.append ( ": " );
        long lastBytes = fc.size () - i;
        for (long j=0; j < 16 && j < lastBytes; j++)
        {
            jta.append ( " " );
            jta.append( myToHexString(mmf.get (),2) );
        }
        jta.append ( "\n" );
        }
    } catch (IOException ex)
    {
        jta.setText ("Error reading file.");
        return;
    }
}
}

static String myToHexString ( long n, int c )
{
    String h= Long.toHexString ( n );
    while( h.length () < c)
    {
    h = "0" + h;
    }
    return h;
}

static String myToHexString( byte n, int c )
{
    int temp = n;
    String h = Integer.toHexString ( 0xFF & temp);
    while(h.length ()<c)
    h = "0"+h;
    return h;
}

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How: convert byte[] to hex encoded string

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