Editor’s Note:This text has changed from the original version.

Have you ever needed toconvert a byte array (byte []) into a displayable hex string? The JDK does notprovide this capability for byte arrays, only for the wrapper classes.

Below is the code which will convert a byte array into a displayable “hex” representation of the string.

Now you can turn

 byte b[] = {0xf1, 0x0d,  0x3c, 0x44};

into:

 String s =  "F10D3C44"

like this:

 String s =  byteArrayToHexString(b);

• provides the same functionality found in Integer.toHexString(), Short.toHexString(), etc…
• Simple to use
• Fast, efficient and accurate
• Tested and proven

Here’s the code:

 /**
* Convert a byte[] array to readable string format. This makes the "hex"readable!
* @return result String buffer in String format 
* @param in byte[] buffer to convert to string format
*/
static String byteArrayToHexString(byte in[]) {
    byte ch = 0x00;
    int i = 0; 
    if (in == null || in.length <= 0)
        return null;
        
    String pseudo[] = {"0", "1", "2","3", "4", "5", "6", "7", "8","9", "A", "B", "C", "D", "E","F"};
    StringBuffer out = new StringBuffer(in.length * 2);
    
    while (i < in.length) {
        ch = (byte) (in[i] & 0xF0); // Strip offhigh nibble
        ch = (byte) (ch >>> 4);     // shift the bits down
        ch = (byte) (ch & 0x0F);    // must do this is high order bit is on!
        out.append(pseudo[ (int) ch]); // convert thenibble to a String Character
        ch = (byte) (in[i] & 0x0F); // Strip offlow nibble 
        out.append(pseudo[ (int) ch]); // convert thenibble to a String Character
        i++;
    }
    String rslt = new String(out);
    return rslt;
}    

Stay tuned, I’ll present some additionalroutines which take the “hex” data and format it into a “Hex Dump”format like: 0000: 32 00 00 00 00 49 99 04 13 14 56 20 17 552B 3F ____[2 I