Get MQ messageId in string format

Question

I\'m using the mq library of IBM to read messages from MQ queues. Now I need to retrieve the messageid of the message. I now it is in the message header under the name messa

Answer 1

The MQMD MessageId field is made up of both character and binary values. Therefore, the only way to properly represent the MessageId field as a String is by converting it to HEX representation.

You need to use my bytesToHex method:

String s = bytesToHex(theMessage.messageId);

Hence, s would look something like '414D51204D5141312020202020202020134CCD4020000B01'.

And the Java code for bytesToHex method is:

public static final String HEX_CHARS = "0123456789ABCDEF";

public static String bytesToHex(byte[] data)
{
   StringBuffer buf = new StringBuffer();
   for (int i = 0; i < data.length; i++)
      buf.append(byteToHex(data[i]));

   return buf.toString();
}

public static String byteToHex(byte data)
{
   int hi = (data & 0xF0) >> 4;
   int lo = (data & 0x0F);
   return "" + HEX_CHARS.charAt(hi) + HEX_CHARS.charAt(lo);
}

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Updated July 23, 2020.

Here is a method to convert a HEX string to a byte array:

public static byte[] hexStringToByteArray(String inString)
{
   byte[] outBuffer = new byte[inString.length()/2];
   String hex;
   int xx;

   for (int i=0, j=0; j < (inString.length() - 1); i++, j+=2)
   {
      hex = inString.substring(j,j+2);
      xx = Integer.parseInt(hex.trim(), 16);
      if (xx < 0)
         xx += 256;

      outBuffer[i] = (byte)xx;
   }

   return outBuffer;
}