java - PDFBox: How to "flatten" a PDF-form?

Question

How do I "flatten" a PDF-form (remove the form-field but keep the text of the field) with PDFBox?

Same question was answered here:

a quick way to do this, is to remove the fields from the acrofrom.

For this you just need to get the document catalog, then the acroform and then remove all fields from this acroform.

The graphical representation is linked with the annotation and stay in the document.

So I wrote this code:

import java.io.File;
import java.util.ArrayList;
import java.util.List;

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDDocumentCatalog;
import org.apache.pdfbox.pdmodel.interactive.form.PDAcroForm;
import org.apache.pdfbox.pdmodel.interactive.form.PDField;

public class PdfBoxTest {
    public void test() throws Exception {
        PDDocument pdDoc = PDDocument.load(new File("E:\Form-Test.pdf"));
        PDDocumentCatalog pdCatalog = pdDoc.getDocumentCatalog();
        PDAcroForm acroForm = pdCatalog.getAcroForm();

        if (acroForm == null) {
            System.out.println("No form-field --> stop");
            return;
        }

        @SuppressWarnings("unchecked")
        List<PDField> fields = acroForm.getFields();

        // set the text in the form-field <-- does work
        for (PDField field : fields) {
            if (field.getFullyQualifiedName().equals("formfield1")) {
                field.setValue("Test-String");
            }
        }

        // remove form-field but keep text ???
        // acroForm.getFields().clear();         <-- does not work
        // acroForm.setFields(null);             <-- does not work
        // acroForm.setFields(new ArrayList());  <-- does not work
        // ???

        pdDoc.save("E:\Form-Test-Result.pdf");
        pdDoc.close();
    }
}

Answer 1

With PDFBox 2 it's now possible to "flatten" a PDF-form easily by calling the flatten method on a PDAcroForm object. See Javadoc: PDAcroForm.flatten().

Simplified code with an example call of this method:

//Load the document
PDDocument pDDocument = PDDocument.load(new File("E:\Form-Test.pdf"));    
PDAcroForm pDAcroForm = pDDocument.getDocumentCatalog().getAcroForm();

//Fill the document
...

//Flatten the document
pDAcroForm.flatten();

//Save the document
pDDocument.save("E:\Form-Test-Result.pdf");
pDDocument.close();

Note: dynamic XFA forms cannot be flatten.

For migration from PDFBox 1.* to 2.0, take a look at the official migration guide.