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up vote -1 down vote favorite

Hi I have the following string

   String msg = "9192939495"

And i want to create the bellow byte

   byte[] texttoprint = {(byte) 0x91, (byte) 0x92,(byte) 0x93,(byte) 0x94,(byte) 0x95}

i try this 

public static byte[] hexStringToByteArray(String s) {
    /*String input = "0102FFAB";*/
    byte[] data = new byte[s.length() / 2];

    for( int i = 0; i < s.length(); i+=2)
    {
      data[i/2] = (byte) Integer.decode( "0x" + s.substring( i, i + 2 )  ).byteValue();
    }
    return data;
}

but it does not works

Also how can I print texttoprint at eclipse log in order to check if everything is OK?

PS if i send to printer {(byte) 0x91, (byte) 0x92,(byte) 0x93,(byte) 0x94,(byte) 0x95} everything is OK but if i sent the result of hexStringToByteArray nothing happens

share|improve this question
    
Why doesn't it work? What happens? –  SLaks Sep 9 '12 at 16:44
    
I sent it to printer but nothing printed... –  kosbou Sep 9 '12 at 16:45
    
how can I print texttoprint at eclipse log in order to check if everything is OK –  kosbou Sep 9 '12 at 16:45
    
@user1081978 try flushing :-) also, you can use Arrays.toString to convert texttoprint into a text representation –  oldrinb Sep 9 '12 at 16:45

1 Answer 1

up vote 0 down vote 
static byte[] decode(final String enc) {
  final long val = Long.parseLong(enc, 16);
  final byte[] raw = new byte[] {
    (byte) ((val & 0xff00000000000000L) >> 56),
    (byte) ((val & 0xff000000000000L) >> 48),
    (byte) ((val & 0xff0000000000L) >> 40),
    (byte) ((val & 0xff00000000L) >> 32),
    (byte) ((val & 0xff000000) >> 24),
    (byte) ((val & 0xff0000) >> 16),
    (byte) ((val & 0xff00) >> 8),
    (byte) (val & 0xff)
  };
  final int n = enc.length() >> 1;
  final byte[] trimmed = new byte[n];
  System.arraycopy(raw, 8 - n, trimmed, 0, n);
  return trimmed;
}

You can print the values using Arrays.toString to convert to text form. To verify they're equal, try using Arrays.equals.

System.out.println(Arrays.equals(texttoprint, hexStringToByteArray("9192939495"))
    ? "success" : "failure");
share|improve this answer
    
sorry but I am java novice and I do not understand how to use the decode... Sorry again –  kosbou Sep 9 '12 at 17:04
    
@user1081978 try decode("9192939495") –  oldrinb Sep 9 '12 at 17:09
    
See here for a working example. –  oldrinb Sep 9 '12 at 17:17

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