Java——pdf增加水印

前言

近期为了知识库文件导出，文件数据安全处理，增加水印处理。

方式一 itextpdf

项目依赖引入

<!-- 文件水印添加 -->
<dependency><groupId>com.itextpdf</groupId><artifactId>itextpdf</artifactId><version>5.5.13</version>
</dependency>
<dependency><groupId>com.itextpdf</groupId><artifactId>itext-asian</artifactId><version>5.2.0</version>
</dependency>

编写PDF添加水印工具类

/*** pdf文件添加文字水印** @param srcPath  输入的文件路径* @param destPath 输出的文件路径* @param word     水印文字* @throws Exception*/
public static void addPDFWaterMark(String srcPath, String destPath, String word)throws Exception {PdfReader reader = new PdfReader(srcPath);PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(destPath));//使用系统字体String prefixFont = null;String os = System.getProperties().getProperty("os.name");if (os.startsWith("win") || os.startsWith("Win")) {// 某些机型可能没有，需要调整prefixFont = "C:\\Windows\\Fonts\\SIMSUN.TTC,1";} else {prefixFont = "/usr/share/fonts/chinese/TrueType/uming.ttf";}//创建字体，第一个参数是字体路径BaseFont base = BaseFont.createFont(prefixFont, BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED);//BaseFont base = BaseFont.createFont("STSong-Light", "UniGB-UCS2-H", BaseFont.EMBEDDED);PdfGState gs = new PdfGState();gs.setFillOpacity(0.1f);//图片水印透明度(数值越大，水印越深)//gs.setStrokeOpacity(0.4f);//设置笔触字体不透明度PdfContentByte content = null;int total = reader.getNumberOfPages();//pdf文件页数for (int i = 0; i < total; i++) {float x = reader.getPageSize(i + 1).getWidth();//页宽度float y = reader.getPageSize(i + 1).getHeight();//页高度content = stamper.getOverContent(i + 1);content.setGState(gs);content.beginText();//开始写入content.setFontAndSize(base, 10);//字体大小(数值越大，字体越大)//每页7行，一行3个for (int j = 0; j < 3; j++) {for (int k = 0; k < 7; k++) {//showTextAligned 方法的参数（文字对齐方式，位置内容，输出水印X轴位置，Y轴位置，旋转角度）content.showTextAligned(Element.ALIGN_CENTER, word, x / 3 * j + 90, y / 7 * k, 25);}}content.endText();//结束写入}//关闭流stamper.close();reader.close();
}

测试

public static void main(String[] args) {// 获取指定路径的pdfFile file = new File("F:\\springboot-stydy\\springboot-pdf-waterMark\\pdf\\22.pdf");try {System.out.println(file.getName());PDFUtil.addPDFWaterMark("F:\\springboot-stydy\\springboot-pdf-waterMark\\pdf\\22.pdf","F:\\springboot-stydy\\springboot-pdf-waterMark\\pdf\\water\\22.pdf" , "香蕉不拿拿(xjbnn)@xiangjiao 2025-04-08");} catch (Exception e) {e.printStackTrace();}
}

效果展示

方式二 pdfbox

依赖引入

<dependency><groupId>org.apache.pdfbox</groupId><artifactId>pdfbox</artifactId><version>2.0.4</version>
</dependency>

编写实现类

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDPageContentStream;
import org.apache.pdfbox.pdmodel.font.PDFont;
import org.apache.pdfbox.pdmodel.font.PDType0Font;
import org.apache.pdfbox.pdmodel.graphics.state.PDExtendedGraphicsState;
import org.apache.pdfbox.util.Matrix;import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;public class PdBoxTest {public static void main(String[] args) throws IOException {// 水印文字String waterMark = "香蕉不拿拿@(xjbnn) "+ LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyy-MM-dd"));// 加载源文件File file = new File("F:\\springboot-stydy\\springboot-pdf-waterMark\\pdf\\22.pdf");// 如果是 inputstream 类的流信息，也可以直接使用 PDDocument.load(inputStream)PDDocument document = PDDocument.load(file);document.setAllSecurityToBeRemoved(true);//使用系统字体String prefixFont = null;String os = System.getProperties().getProperty("os.name");if (os.startsWith("win") || os.startsWith("Win")) {// 仿宋 简体 常规 (其他类型会报错)prefixFont = "C:\\Windows\\Fonts\\simfang.ttf";} else {prefixFont = "/usr/share/fonts/chinese/TrueType/uming.ttf";}PDFont font = PDType0Font.load(document, new FileInputStream(prefixFont), true);// 读取pdf文件，将每一页中都增加水印for (PDPage page : document.getPages()) {PDPageContentStream stream = new PDPageContentStream(document, page, PDPageContentStream.AppendMode.APPEND, true, true);PDExtendedGraphicsState r = new PDExtendedGraphicsState();// 设置透明度r.setNonStrokingAlphaConstant(0.1f);r.setAlphaSourceFlag(true);stream.setGraphicsStateParameters(r);//开始写入stream.beginText();stream.setFont(font, 10);stream.newLineAtOffset(0, -15);// 获取PDF页面大小float pageHeight = page.getMediaBox().getHeight();float pageWidth = page.getMediaBox().getWidth();// 根据纸张大小添加水印，30度倾斜for (int h = 10; h < pageHeight; h = h + 150) {for (int w = - 10; w < pageWidth; w = w + 150) {stream.setTextMatrix(Matrix.getRotateInstance(0.3, w, h));stream.showText(waterMark);}}// 结束渲染，关闭流stream.endText();stream.restoreGraphicsState();stream.close();}// 将加工后的文件写入到新的文件中File outFile = new File("F:\\springboot-stydy\\springboot-pdf-waterMark\\pdf\\water\\pdbox.pdf");document.save(outFile);document.close();}
}

效果展示

扩展

1、将inputstream流信息添加水印并导出zip

使用pdfbox更方便处理。如下工具类：

/*** 添加水印并打包压缩* @param inputStream 文件输入流信息* @param path 文件路径* @param zipOutputStream zip压缩包* @param waterMark 水印* @param rowSpace 行间距，大中小分别对应150/100/50* @param colSpace 列间距，大中小分别对应150/100/50* @throws Exception*/
private void addPDFWaterMarkAndZip(InputStream inputStream,String path, ZipOutputStream zipOutputStream, String waterMark,int rowSpace,int colSpace)throws Exception {PDDocument document = PDDocument.load(inputStream);document.setAllSecurityToBeRemoved(true);//使用系统字体String prefixFont = null;String os = System.getProperties().getProperty("os.name");if (os.startsWith("win") || os.startsWith("Win")) {prefixFont = "C:\\Windows\\Fonts\\simfang.ttf";} else {prefixFont = "/usr/share/fonts/chinese/TrueType/uming.ttf";}PDFont font = PDType0Font.load(document, new FileInputStream(prefixFont), true);for (PDPage page : document.getPages()) {PDPageContentStream stream = new PDPageContentStream(document, page, PDPageContentStream.AppendMode.APPEND, true, true);PDExtendedGraphicsState r = new PDExtendedGraphicsState();// 设置透明度r.setNonStrokingAlphaConstant(0.1f);r.setAlphaSourceFlag(true);stream.setGraphicsStateParameters(r);//开始写入stream.beginText();stream.setFont(font, 10);stream.newLineAtOffset(0, -15);// 获取PDF页面大小float pageHeight = page.getMediaBox().getHeight();float pageWidth = page.getMediaBox().getWidth();// 根据纸张大小添加水印，30度倾斜for (int h = 10; h < pageHeight; h = h + rowSpace) {for (int w = - 10; w < pageWidth; w = w + colSpace) {stream.setTextMatrix(Matrix.getRotateInstance(0.3, w, h));stream.showText(waterMark);}}// 结束渲染，关闭流stream.endText();stream.restoreGraphicsState();stream.close();}// 创建临时的文件String snowflakeNextIdStr = IdUtil.getSnowflakeNextIdStr();File tempFile = File.createTempFile(snowflakeNextIdStr, ".pdf");// 加了水印的文件暂存临时文件document.save(tempFile);document.close();// 获取临时文件的数据流InputStream fileInputStream = new FileInputStream(tempFile);// 加入 zipZipEntry ze = new ZipEntry(path);zipOutputStream.putNextEntry(ze);byte[] buffer = new byte[1024];int len;while ((len = fileInputStream.read(buffer)) > 0) {zipOutputStream.write(buffer, 0, len);}fileInputStream.close();// 删除临时文件tempFile.delete();}

然后再调用处使用：

response.setContentType("application/force-download");
response.setCharacterEncoding("UTF-8");
response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, StandardCharsets.UTF_8));
ZipOutputStream zipOutputStream = new ZipOutputStream(response.getOutputStream());

2、部署出现找不到指定字体文件

可以在项目中的src/main/resource/下放入字体文件。如下

然后修改字体获取方式，如下：

String ttfPath = Thread.currentThread().getContextClassLoader().getResource("font/simfang.ttf").getPath();PDFont font = PDType0Font.load(document, new FileInputStream(ttfPath));

资料参考

V少年如他-Java实现PDF文件添加水印
Shacoray-Java针对不同文件加水印
PDF格式怎么加水印？