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!

score 67 · Accepted Answer · edited Nov 17 '09 at 11:14

67

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 '09 at 11:14

Adeel Ansari

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answered Nov 17 '09 at 10:51

bruno conde

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4

Of all of these, the `System.out.printf` is probably the best idea. – abyx Nov 17 '09 at 11:18
2

But the `Integer.toHexString` will print `10` not `0x0A`. – Anirban Nag 'tintinmj' Feb 01 '14 at 18:40

score 8 · Answer 2 · answered Nov 17 '09 at 11:00

8

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

answered Nov 17 '09 at 11:00

Carl Smotricz

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score 3 · Answer 3 · edited Feb 17 '12 at 17:55

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 '12 at 17:55

Dan Rosenstark

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answered Nov 17 '09 at 10:55

jeff porter

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You can definitely do byte b = 255 & 0xFF; And then when reading it int calculation = (0xFF &b) + 5; to read back 255 – Per Christian Henden Mar 21 '14 at 08:59

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

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