Add, Extract and Remove Attachments in a PDF document using Java

This article will introduce how to add, extract and remove attachments in a PDF document using Java codes programmatically. Before beginning, we should create a test environment using a free third-party library called FreeSpire.PDF for Java. You can either download the API’s JAR or install it within your maven-based applications using the following configurations.

<repositories>
<repository>
<id>com.e-iceblue</id>
<name>e-iceblue</name>
<url>http://repo.e-iceblue.com/nexus/content/groups/public/</url>
</repository>
</repositories>
<dependencies>
<dependency>
<groupId> e-iceblue </groupId>
<artifactId>spire.pdf.free</artifactId>
<version>3.9.0</version>
</dependency>
</dependencies>

Add Attachments to PDF in Java
Free Spire.PDF for Java supports adding a file attachment or annotation attachment to PDF. In the 
process of adding an annotation attachment, it supports drawing a label on PDF, and set the label’s font 
size or location. Besides, Flag, icon or text can be also set.
The following code sample shows how to add a file attachment and an annotation attachment.
import com.spire.pdf.PdfDocument;
import com.spire.pdf.annotations.*;
import com.spire.pdf.attachments.PdfAttachment;
import com.spire.pdf.graphics.*;
import java.awt.*;
import java.awt.geom.Dimension2D;
import java.awt.geom.Rectangle2D;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

public class AddAttachment {
    public static void main(String[] args) throws IOException {
        //create a PdfDocument object
        PdfDocument doc = new PdfDocument();

        //load a sample PDF file
        doc.loadFromFile("C:\\Users\\Test1\\Desktop\\Sample.pdf");

        //add an attachment to pdf
        PdfAttachment attachment = new PdfAttachment("C:\\Users\\Test1\\Desktop\\Country list.xlsx");
        doc.getAttachments().add(attachment);

        //draw a label on pdf
        String label = "Report.docx";
        PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("Arial", Font.BOLD, 14));
        double x = 30;
        double y = doc.getPages().get(2).getActualSize().getHeight() - 80;
        doc.getPages().get(2).getCanvas().drawString(label, font, PdfBrushes.getOrange(), x, y);

        //add an attachment annotation to pdf
        String filePath = "C:\\Users\\Test1\\Desktop\\Report.docx";
        byte[] data = toByteArray(filePath);
        Dimension2D size = font.measureString(label);
        Rectangle2D bound = new Rectangle2D.Float((float) (x + size.getWidth() + 2), (float) y, 10, 15);
        PdfAttachmentAnnotation annotation = new PdfAttachmentAnnotation(bound, filePath, data);
        annotation.setColor(new PdfRGBColor(new Color(128, 13, 119)));
        annotation.setFlags(PdfAnnotationFlags.Default);
        annotation.setIcon(PdfAttachmentIcon.Graph);
        annotation.setText("Click to open Report.docx");
        doc.getPages().get(2).getAnnotationsWidget().add(annotation);

        //save to file
        doc.saveToFile("output/AddAttachments.pdf");
    }

    //read file to byte array
    public static byte[] toByteArray(String filePath) throws IOException {

        File file = new File(filePath);
        long fileSize = file.length();
        if (fileSize > Integer.MAX_VALUE) {
            System.out.println("file too big...");
            return null;
        }
        FileInputStream fi = new FileInputStream(file);
        byte[] buffer = new byte[(int) fileSize];
        int offset = 0;
        int numRead = 0;
        while (offset < buffer.length
                && (numRead = fi.read(buffer, offset, buffer.length - offset)) >= 0) {
            offset += numRead;
        }

        if (offset != buffer.length) {
            throw new IOException("Could not completely read file "
                    + file.getName());
        }
        fi.close();
        return buffer;
    }
}
Output

Extract Attachments from PDF
We just need to load the sample file, get and loop through the attachment collection to extract each 
attachment in PDF.
import com.spire.pdf.PdfDocument;
import com.spire.pdf.attachments.PdfAttachmentCollection;
import java.io.*;

public class ExtractAttachment {
    public static void main(String[] args) throws IOException {
        //Load the PDF document
        PdfDocument pdf = new PdfDocument();
        pdf.loadFromFile("C:\\Users\\Test1\\Desktop\\AddAttachments.pdf");

        //Get the attachment collection of the PDF document
        PdfAttachmentCollection attachments = pdf.getAttachments();

        //Loop through the collection and extract each attachment in the PDF document
        for (int i = 0; i < attachments.getCount(); i++) {
            File file = new File("output/ExtractAttachments/"+attachments.get(i).getFileName());
            OutputStream output = new FileOutputStream(file);

            BufferedOutputStream bufferedOutput = new BufferedOutputStream(output);

            bufferedOutput.write(attachments.get(i).getData());
            bufferedOutput.close();
        }
    }
}
Delete Attachments in PDF
We can separately delete a file attachment or an annotation attachment from the following two code 
samples.
l  Delete a file attachment
Free Spire.PDF for Java supports delete all attachments or a specific attachment in PDF.
import com.spire.pdf.PdfDocument;
import com.spire.pdf.attachments.PdfAttachmentCollection;
public class DeleteAttachment {
    public static void main(String[] args) {
        //load a PDF document
        PdfDocument doc = new PdfDocument();
        doc.loadFromFile("C:\\Users\\Test1\\Desktop\\AddAttachments.pdf");

        //get the attachments collection, not containing annotation attachments
        PdfAttachmentCollection attachments = doc.getAttachments();

        //remove all attachments
        attachments.clear();

        //remove a specific attachment
        //attachments.removeAt(0);

        //save to file
        doc.saveToFile("output/DeleteAttachments.pdf");
        doc.close();
    }
}
l  Delete an annotation attachment
We can delete the annotation attachment by determining if it is an instance of PdfAttachmentAnnotationWidget
in the following code sample.
import com.spire.pdf.PdfDocument;
import com.spire.pdf.annotations.PdfAnnotation;
import com.spire.pdf.annotations.PdfAnnotationCollection;
import com.spire.pdf.annotations.PdfAttachmentAnnotationWidget;
public class DeleteAnnotationAttachment {
    public static void main(String[] args) {
        //load a PDF document
        PdfDocument doc = new PdfDocument();
        doc.loadFromFile("C:\\Users\\Test1\\Desktop\\AddAttachments.pdf");

        //loop through the pages
        for (int i = 0; i < doc.getPages().getCount(); i++) {

            //get the annotations collection
            PdfAnnotationCollection annotationCollection = doc.getPages().get(i).getAnnotationsWidget();

            //loop through the annotations
            for (Object annotation: annotationCollection) {

                //determine if an annotation is an instance of PdfAttachmentAnnotationWidget
                if (annotation instanceof PdfAttachmentAnnotationWidget){

                    //remove the attachment annotation
                    annotationCollection.remove((PdfAnnotation) annotation);
                }
            }
        }
        //save to file
        doc.saveToFile("output/DeleteAnnotationAttachments.pdf");
        doc.close();
    }
}