How do I unpack an ISO 8583 message?

The code snippet below will show you how to unpack ISO 8583 message.

package org.kodejava.jpos;

import org.jpos.iso.ISOException;
import org.jpos.iso.ISOMsg;
import org.jpos.iso.packager.GenericPackager;

import java.io.InputStream;

public class UnpackISOMessage {
    public static void main(String[] args) {
        UnpackISOMessage iso = new UnpackISOMessage();
        try {
            ISOMsg isoMsg = iso.parseISOMessage();
            iso.printISOMessage(isoMsg);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private ISOMsg parseISOMessage() throws Exception {
        String message = "02003220000000808000000010000000001500120604120000000112340001840";
        System.out.printf("Message = %s%n", message);
        try {
            // Load package from resources directory.
            InputStream is = getClass().getResourceAsStream("/fields.xml");
            GenericPackager packager = new GenericPackager(is);
            ISOMsg isoMsg = new ISOMsg();
            isoMsg.setPackager(packager);
            isoMsg.unpack(message.getBytes());
            return isoMsg;
        } catch (ISOException e) {
            throw new Exception(e);
        }
    }

    private void printISOMessage(ISOMsg isoMsg) {
        try {
            System.out.printf("MTI = %s%n", isoMsg.getMTI());
            for (int i = 1; i <= isoMsg.getMaxField(); i++) {
                if (isoMsg.hasField(i)) {
                    System.out.printf("Field (%s) = %s%n", i, isoMsg.getString(i));
                }
            }
        } catch (ISOException e) {
            e.printStackTrace();
        }
    }
}

When you run the program you’ll get the following output:

Message = 02003220000000808000000010000000001500120604120000000112340001840
MTI = 0200
Field (3) = 000010
Field (4) = 000000001500
Field (7) = 1206041200
Field (11) = 000001
Field (41) = 12340001
Field (49) = 840

The xml packager (fields.xml) can be downloaded from the following link: fields.xml.

Maven Dependency

<dependency>
    <groupId>org.jpos</groupId>
    <artifactId>jpos</artifactId>
    <version>2.1.8</version>
</dependency>