使用pdfbox 为 PDF增加水印https://www.jylt.cc/#/detail?activityIndex=2&id=bd410851b0a72dad3105f9d50787f914

引入依赖

<dependency><groupId>org.apache.pdfbox</groupId><artifactId>pdfbox</artifactId><version>3.0.1</version>
</dependency>
<!--下面操作图片的时候需要用到该工具类-->
<dependency><groupId>cn.hutool</groupId><artifactId>hutool-core</artifactId><version>5.8.25</version>
</dependency>

具体代码实现

public static void main(String[] args) throws Exception {// 读取原始 PDF 文件PDDocument document = PDDocument.load(new File("/Users/a58/Downloads/test.pdf"));File file = new File("/Users/picture/Downloads/waterMark.png");BufferedOutputStream outputStream = FileUtil.getOutputStream(file);FileImageOutputStream fileImageOutputStream = new FileImageOutputStream(file);// 创建文字图片Font font = new Font("宋体", Font.PLAIN, 12);Color fontColor = new Color(100, 100, 100, 60);ImgUtil.createImage("水印", font, null, fontColor, fileImageOutputStream);// 旋转图片，使水印倾斜ImgUtil.rotate(file, -20, file);// 遍历 PDF 中的所有页面for (int i = 0; i < document.getNumberOfPages(); i++) {PDPage page = document.getPage(i);PDPageContentStream contentStream = new PDPageContentStream(document, page, PDPageContentStream.AppendMode.APPEND, true, true);// PDF页面宽度float pageWidth = page.getMediaBox().getWidth();// PDF页面高度float pageHeight = page.getMediaBox().getHeight();// 4：每页有4列水印int xBegin = (int) (pageWidth / 4);// 8：每页有8行水印int yBegin = (int) (pageHeight / 8);// 加载图片PDImageXObject pdImageXObject = PDImageXObject.createFromFile(file.getAbsolutePath(), document);float width = pdImageXObject.getWidth();float height = pdImageXObject.getHeight();for (int yIndex = 0; yIndex < 8; yIndex++) {for (int xIndex = 0; xIndex < 4; xIndex++) {contentStream.drawImage(pdImageXObject, (xBegin * xIndex) + 5, (yBegin * yIndex), width, height);}yIndex++;}contentStream.close();}// 保存修改后的 PDF 文件document.save(new File("/Users/picture/Downloads/testout.pdf"));document.close();System.out.println("完成");}