This sample finds fields in a PDF file and identifies any barcode fields then prints it's value to System.out.

ReadBarcodeFieldFromPDF.java

/*
 * Copyright Datalogics, Inc. 2015
 */

package pdfjt.cookbook.forms;

import com.adobe.internal.io.ByteReader;
import com.adobe.internal.io.InputStreamByteReader;
import com.adobe.pdfjt.pdf.document.PDFDocument;
import com.adobe.pdfjt.pdf.document.PDFOpenOptions;
import com.adobe.pdfjt.pdf.interactive.annotation.PDFAnnotationWidget;
import com.adobe.pdfjt.pdf.interactive.forms.PDFField;
import com.adobe.pdfjt.pdf.interactive.forms.PDFInteractiveForm;

import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.util.Iterator;

/**
 * This sample finds fields in a PDF file and identifies any barcode fields then
 * prints it's value to System.out.
 */
public class ReadBarcodeFieldFromPDF {

    private static final String inputPDFURL = "http://dev.datalogics.com/cookbook/forms/ReadBarcodeField.pdf";

    public static void main(String[] args) throws Exception {
        /*
         * Read in PDF input file
         */
        URLConnection connection = new URL(inputPDFURL).openConnection();
        connection.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.95 Safari/537.11");
        connection.connect();
        InputStream fis = connection.getInputStream();        
        ByteReader byteReader = new InputStreamByteReader(fis);
        PDFDocument pdfDocument = PDFDocument.newInstance(byteReader, PDFOpenOptions.newInstance());
        PDFInteractiveForm pdfInteractiveForm = pdfDocument.getInteractiveForm();
        if (pdfInteractiveForm != null) {
            // Get Field iterator
            Iterator<PDFField> fieldIterator = pdfInteractiveForm.iterator();
            // Iterator over form fields
            while (fieldIterator.hasNext()) {
                PDFField pdfField = (PDFField) (fieldIterator.next());
                /*
                 * Barcode fields are really text fields with special
                 * appearances so we only need to look for PDFFieldText objects.
                 */
                if (pdfField.getClass().getSimpleName().matches("PDFFieldText")) {
                    /*
                     * Assume the field is terminal and likely to be combined
                     * with it's annotation.
                     */
                    if (pdfField.isAnnotation()) {
                        /*
                         * Get the first, and probably only, annotation
                         * associated with the field. If the barcode appears on
                         * more than one page, this may not be the case.
                         */
                        PDFAnnotationWidget pdfAnnotationWidget = (PDFAnnotationWidget) pdfField.getAnnotationsIterator().next();
                        /*
                         * Finally we have an object that we can interrogate to
                         * see if it is a barcode widget. PMD stands for
                         * "Paper Metadata".
                         */
                        if (pdfAnnotationWidget.hasPMD()) {
                            // We've identified a barcode widget
                            if (pdfField.getValueList() != null) {
                                System.out.println("Barcode Field Found: " + pdfField.getQualifiedName());
                                System.out.println(pdfField.getValueList().get(0));
                            }
                        }
                    }
                }
            }
        }
    }
}