java pdf添加水印

spring boot pdf添加水印以下代码仅供参考

导入jar包（pdfbox）

        <dependency>
            <groupId>org.apache.pdfbox</groupId>
            <artifactId>pdfbox</artifactId>
            <version>2.0.12</version>
        </dependency>

代码如下

package com.watermark.utils;

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDPageContentStream;
import org.apache.pdfbox.pdmodel.PDResources;
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 org.springframework.util.ResourceUtils;

import java.io.File;
import java.io.InputStream;

public class PDFWatermark {
    
    public static void main(String[] args) {
        try {
            watermark(new File("E:\\xx.pdf"));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    private static void watermark(File file) throws Exception {
        //创建新pdf文件
        File tmpPDF = new File("E:\\demo_" + file.getName());
        //打开pdf文件
        PDDocument doc = PDDocument.load(file);
        doc.setAllSecurityToBeRemoved(true);
        //遍历pdf所有页
        for (PDPage page : doc.getPages()) {
            PDPageContentStream cs = new PDPageContentStream(doc, page, PDPageContentStream.AppendMode.APPEND, true, true);
            String ts = "测试水印测试";
            //引入字体文件 解决中文汉字乱码问题
            PDFont font = PDType0Font.load(doc, new FileInputStream("E:\\微软雅黑.ttf"), true);
            float fontSize = 30;
            PDResources resources = page.getResources();
            PDExtendedGraphicsState r0 = new PDExtendedGraphicsState();
            // 水印透明度
            r0.setNonStrokingAlphaConstant(0.2f);
            r0.setAlphaSourceFlag(true);
            cs.setGraphicsStateParameters(r0);
            //水印颜色
            cs.setNonStrokingColor(200, 0, 0);

            cs.beginText();
            cs.setFont(font, fontSize);
            //根据水印文字大小长度计算横向坐标需要渲染几次水印
            float h = ts.length() * fontSize;
            for (int i = 0; i <= 10; i++) {
                // 获取旋转实例
                cs.setTextMatrix(Matrix.getRotateInstance(-150, i * 100, 0));
                cs.showText(ts);
                for (int j = 0; j < 20; j++) {
                    cs.setTextMatrix(Matrix.getRotateInstance(-150, i * 100, j * h));
                    cs.showText(ts);
                }
            }
            cs.endText();
            cs.restoreGraphicsState();
            cs.close();
        }
        doc.save(tmpPDF);
    }
}

最终效果