Convert Integer to Hex String

Question

i have an Integer value and i want to convert it on Hex.

i do this:

private short getCouleur(Integer couleur, HSSFWorkbook classeur) {
if (null == couleur) {
    return WHITE.index;
} else {
    HSSFPalette palette = classeur.getCustomPalette();
    String hexa = Integer.toHexString(couleur);

    byte r = Integer.valueOf(hexa.substring(0, 2), 16).byteValue();
    byte g = Integer.valueOf(hexa.substring(2, 4), 16).byteValue();
    byte b = Integer.valueOf(hexa.substring(4, 6), 16).byteValue();

    palette.setColorAtIndex((short) 65, r, g, b);

    return (short) 65;
}
}

In output i have this:

couleur: 65331

Hexa: FF33

hexa.substring(0, 2): FF

hexa.substring(2, 4): 33

hexa.substring(4, 6):

r: -1

g: 51

b: error message

error message: String index out of range: 6

Thx.

already answered here - stackoverflow.com/questions/5258415/… — radai
– radai, Commented Nov 22, 2013 at 8:46
You must pad the hex string before extracting the byte arrays. Already answered here: stackoverflow.com/questions/5446863/… — home
– home, Commented Nov 22, 2013 at 8:52

PoWen · Accepted Answer · 2013-11-22 09:01:29Z

6

you can call the method in JDK.

String result = Integer.toHexString(131);

answered Nov 22, 2013 at 9:01

PoWen

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Comments

Adam Dyga · Accepted Answer · 2013-11-22 09:20:14Z

4

If I understand correctly you want to split an int into three bytes (R, G, B). If so, then you can do this by simply shifting the bits in the integer:

byte r = (byte)((couleur >> 16) & 0x000000ff);
byte g = (byte)((couleur >> 8) & 0x000000ff);
byte b = (byte)(couleur & 0x000000ff);

That's much more efficient. You don't have to do it through conversion to String.

edited Nov 22, 2013 at 9:20

answered Nov 22, 2013 at 8:57

Adam Dyga

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1 Comment

Mercer Over a year ago

Type mismatch: cannot convert from int to byte

Scary Wombat · Accepted Answer · 2013-11-22 08:52:30Z

2

The problem is that you are assuming that the hex string will be six digits long.

try String.format ("%06d", Integer.toHexString(couleur));

to pad it with zeros if less than 6 digits longs

answered Nov 22, 2013 at 8:52

Scary Wombat

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