<!-- Apache POI -->
<dependency>
  <groupId>org.apache.poi</groupId>
  <artifactId>poi</artifactId>
  <version>4.1.2</version>
</dependency>
<dependency>
  <groupId>org.apache.poi</groupId>
  <artifactId>poi-ooxml</artifactId>
  <version>4.1.2</version>
</dependency>

<!-- OpenPDF -->
<dependency>
  <groupId>com.lowagie</groupId>
  <artifactId>itext</artifactId>
  <version>2.1.7</version>
</dependency>

import com.itextpdf.text.*;
import com.itextpdf.text.pdf.*;

import java.io.IOException;

public class Watermark implements PdfPageEvent {
    private final String text;

    public Watermark(String text) {
        this.text = text;
    }

    @Override
    public void onEndPage(PdfWriter writer, Document document) {
        PdfContentByte canvas = writer.getDirectContentUnder();
        Phrase watermark = new Phrase(text, new Font(FontFamily.HELVETICA, 52, Font.NORMAL, BaseColor.LIGHT_GRAY));

        Rectangle rect = new Rectangle(document.getPageSize());
        rect.setBorder(Rectangle.BOX);
        rect.setBorderWidth(1);
        rect.setBorderColor();
        rect.setUseVariableBorders(true);

        ColumnText.showTextAligned(canvas, Element.ALIGN_CENTER, watermark, 0, 0, 45);
        canvas.rectangle(rect);
        canvas.stroke();
    }
}

public class Signature implements PdfPageEvent {
    private static final int FONT_SIZE = 14;
    private static final int IMAGE_SIZE = 100;
    private final String imagePath;
    private final String signatureText;

    public Signature(String imagePath, String signatureText) {
        this.imagePath = imagePath;
        this.signatureText = signatureText;
    }

    @Override
    public void onEndPage(PdfWriter writer, Document document) {
        try {
            // 添加簽名
            Image image = Image.getInstance(imagePath);
            image.scaleAbsolute(IMAGE_SIZE, IMAGE_SIZE);
            image.setAbsolutePosition((document.getPageSize().getWidth() - image.getScaledWidth()) / 2,
                    (document.getPageSize().getHeight() - image.getScaledHeight()) / 2);

            // 添加蓋章
            PdfContentByte canvas = writer.getDirectContent();
            BaseFont font = BaseFont.createFont("STSong-Light", "UniGB-UCS2-H", BaseFont.NOT_EMBEDDED);
            canvas.beginText();
            canvas.setFontAndSize(font, FONT_SIZE);
            canvas.showTextAligned(Element.ALIGN_CENTER, signatureText,
                    document.getPageSize().getWidth() - 80, 120, 0);
            canvas.endText();

            canvas.addImage(image);
        } catch (IOException | BadElementException e) {
            throw new RuntimeException(e);
        }
    }
}

import com.itextpdf.text.*;
import com.itextpdf.text.pdf.*;
import org.apache.poi.xwpf.usermodel.XWPFDocument;
import org.apache.poi.xwpf.usermodel.XWPFParagraph;
import org.apache.poi.xwpf.usermodel.XWPFTable;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.InputStream;

public class WordToPdfConverter {
    public static InputStream convert(String wordFilePath, String signatureImagePath, String signatureText) {
        try (FileInputStream fis = new FileInputStream(wordFilePath);
             XWPFDocument document = new XWPFDocument(fis);
             ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
            PdfWriter writer = PdfWriter.getInstance(document, baos);
            writer.setPageEvent(new Watermark("Confidential"));
            writer.setPageEvent(new Signature(signatureImagePath, "Approved"));

            Document pdfDoc = new Document();
            pdfDoc.open();
            for (IBodyElement element : document.getBodyElements()) {
                if (element instanceof XWPFParagraph) {
                    XWPFParagraph paragraph = (XWPFParagraph) element;
                    pdfDoc.add(new Paragraph(paragraph.getText()));
                } else if (element instanceof XWPFTable) {
                    XWPFTable table = (XWPFTable) element;
                    pdfDoc.add(new Paragraph(table.getText()));
                }

                pdfDoc.newPage(); // 每一頁添加水印、簽名和蓋章
            }
            pdfDoc.close();

            return new ByteArrayInputStream(baos.toByteArray());
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}

import java.io.FileOutputStream;
import java.io.InputStream;

public class Main {
    public static void main(String[] args) throws Exception {
        // 將Word文檔轉(zhuǎn)換為PDF并添加水印、簽名和蓋章
        InputStream pdfStream = WordToPdfConverter.convert("input.docx", "signature.png", "Approved");

        // 將PDF保存到文件
        try (FileOutputStream fos = new FileOutputStream("output.pdf")) {
            byte[] buffer = new byte[1024];
            int bytesRead;
            while ((bytesRead = pdfStream.read(buffer)) != -1) {
                fos.write(buffer, 0, bytesRead);
            }
        }

        System.out.println("PDF generated successfully.");
    }
}