How to print bytes in hexadecimal using System.out.println?

Question

I've declared a byte array (I'm using Java):

byte test[] = new byte[3];
test[0] = 0x0A;
test[1] = 0xFF;
test[2] = 0x01;

How could I print the different values stored in the array?

If I use System.out.println(test[0]) it will print '10'. I'd like it to print 0x0A

Thanks to everyone!

Adeel Ansari · Accepted Answer · 2009-11-17 11:14:34Z

68

System.out.println(Integer.toHexString(test[0]));

OR (pretty print)

System.out.printf("0x%02X", test[0]);

OR (pretty print)

System.out.println(String.format("0x%02X", test[0]));

edited Nov 17, 2009 at 11:14

Adeel Ansari

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answered Nov 17, 2009 at 10:51

bruno conde

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2 Comments

abyx Over a year ago

Of all of these, the System.out.printf is probably the best idea.

Anirban Nag 'tintinmj' Over a year ago

But the Integer.toHexString will print 10 not 0x0A.

Carl Smotricz · Accepted Answer · 2009-11-17 11:00:27Z

9

for (int j=0; j<test.length; j++) {
   System.out.format("%02X ", test[j]);
}
System.out.println();

answered Nov 17, 2009 at 11:00

Carl Smotricz

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Comments

Dan Rosenstark · Accepted Answer · 2012-02-17 17:55:23Z

3

byte test[] = new byte[3];
test[0] = 0x0A;
test[1] = 0xFF;
test[2] = 0x01;

for (byte theByte : test)
{
  System.out.println(Integer.toHexString(theByte));
}

NOTE: test[1] = 0xFF; this wont compile, you cant put 255 (FF) into a byte, java will want to use an int.

you might be able to do...

test[1] = (byte) 0xFF;

I'd test if I was near my IDE (if I was near my IDE I wouln't be on Stackoverflow)

edited Feb 17, 2012 at 17:55

Dan Rosenstark

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answered Nov 17, 2009 at 10:55

jeff porter

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1 Comment

Per Christian Henden Over a year ago

You can definitely do byte b = 255 & 0xFF; And then when reading it int calculation = (0xFF &b) + 5; to read back 255

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