gistfile1.java

import java.util.List;
import java.io.FileWriter;
import java.io.BufferedWriter;
import java.nio.ByteBuffer;
import javax.smartcardio.*;

class ProxNRollReader {
  byte[] GET_UID = {(byte)0xFF, (byte)0xCA, (byte)0x00,
								    (byte)0x00, (byte)0x00};

  public static void main(String[] args) {
    if (args.length < 1) {
      System.out.println("usage: java ProxNRollReader <file_to_output>");
      System.exit(1);
    }
    new ProxNRollReader().start(args[0]);
  }
  
  public void start(String fileToOutput) {
    FileWriter file;
    BufferedWriter out;
    try {
      file = new FileWriter(fileToOutput);
      out = new BufferedWriter(file);
    } catch (Exception e) {
      System.err.println("error opening file!");
      e.printStackTrace();
      return;
    }
    
    String currentUID = "";
    while (true) {
      try {
        TerminalFactory factory = TerminalFactory.getDefault();
        List<CardTerminal> terminals = factory.terminals().list();
        CardTerminal reader = null;

        for (CardTerminal terminal: terminals) {
          if (terminal.getName().contains("SpringCard")) {
            reader = terminal;
            break;
          }          
        }

        if (reader != null) {
          while (reader.waitForCardPresent(0)) {            
            Card card = reader.connect("*");
            CardChannel channel = card.getBasicChannel();

            String newUID = sendToChannel(GET_UID, channel);
            card.disconnect(false);
            if (!newUID.equals("") && !newUID.equals(currentUID)) {
              System.out.println(newUID);
              out.write(newUID);
              out.newLine();
              out.flush();
            }
            currentUID = newUID;
            reader.waitForCardAbsent(0);
          }
        } else {
          System.out.println("no readers.");
          Thread.sleep(500);
        }
      } catch (Exception e) {
        System.err.println("E: "+e);
        e.printStackTrace();
      }
    }
  }
  
  private String sendToChannel(byte[] cmd, CardChannel channel) {
    String res = "";
    try {
      ResponseAPDU output = channel.transmit(new CommandAPDU(cmd));
      if (0x9000 != output.getSW()) {
        System.err.println("SELECT ERROR");
        return "";
      }
	
  	  byte[] received = output.getData();

  	  for (int ii = 0; ii < 8 - received.length; ii++) {
  	    res += "00";
	    }
      for (int ii = 0; ii < received.length; ii++) {
        res += String.format("%02X", received[ii]);
      }

    } catch (CardException ex) {
      System.err.println("Caught exception on channel: " + ex);
      ex.printStackTrace();
      
    }
    return res;
  }
}