Question

I am new to java card.

i have this code…..so please tell me how to read data from smart card using java card

        private void readName(APDU apdu) throws ISOException
    {
      byte[] apduBuffer = apdu.getBuffer();
      for (byte i=0; i<userName.length; i++)
      {
        apduBuffer[5+i] = userName[(byte)i] ;
      }
      apdu.setOutgoing();
      apdu.setOutgoingLength((short)userName.length);
      apdu.sendBytes((short)5, (short)userName.length);
    }

Answer 1

The common mechanism to read data from files in smart card is:

1. select the file (EF), follow the rules, you can’t blindly select as in desktop computer filesystem
2. send read binary/record depending on EF type (read binary for transparent EF, read record for linear fixed/cyclic EF)
3. send get response to get the EF contents