1.添加maven依赖

 

<dependency>
            <groupId>com.itextpdf</groupId>
            <artifactId>itextpdf</artifactId>
            <version>5.5.6</version>
        </dependency>

 

2.获得透明的png格式的电子印章图片的工具类

 

package lucky.aozhan.user.utils;

import javax.imageio.ImageIO;
import javax.swing.*;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.*;

public class PNGchange {
    public static void main(String[] args) {
        System.out.println(transferAlpha2File("D:\\resource\\yinzhang\\aozhanyzimg.png", "D:\\resource\\yinzhang\\aozhanyzimg_1.png"));
    }

    public static boolean transferAlpha2File(String imgSrc, String imgTarget) {
        File file = new File(imgSrc);
        InputStream is = null;
        boolean result = false;
        try {
            is = new FileInputStream(file);
            // 如果是MultipartFile类型，那么自身也有转换成流的方法：is = file.getInputStream();
            BufferedImage bi = ImageIO.read(is);
            Image image = (Image) bi;
            ImageIcon imageIcon = new ImageIcon(image);
            BufferedImage bufferedImage = new BufferedImage(imageIcon.getIconWidth(), imageIcon.getIconHeight(),
                    BufferedImage.TYPE_4BYTE_ABGR);
            Graphics2D g2D = (Graphics2D) bufferedImage.getGraphics();
            g2D.drawImage(imageIcon.getImage(), 0, 0, imageIcon.getImageObserver());
            int alpha = 0;
            for (int j1 = bufferedImage.getMinY(); j1 < bufferedImage.getHeight(); j1++) {
                for (int j2 = bufferedImage.getMinX(); j2 < bufferedImage.getWidth(); j2++) {
                    int rgb = bufferedImage.getRGB(j2, j1);
                    int R = (rgb & 0xff0000) >> 16;
                    int G = (rgb & 0xff00) >> 8;
                    int B = (rgb & 0xff);
                    if (((255 - R) < 30) && ((255 - G) < 30) && ((255 - B) < 30)) {
                        rgb = ((alpha + 1) << 24) | (rgb & 0x00ffffff);
                    }
                    bufferedImage.setRGB(j2, j1, rgb);
                }
            }
            g2D.drawImage(bufferedImage, 0, 0, imageIcon.getImageObserver());
            result = ImageIO.write(bufferedImage, "png", new File(imgTarget));// 直接输出文件
        } catch (Exception e) {
            e.printStackTrace();
            result = false;
        } finally {
            if (is != null) {
                try {
                    is.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                }
            }
        }
        return result;
    }

    public static byte[] transferAlpha2Byte(String imgSrc) {
        ByteArrayOutputStream byteArrayOutputStream = null;
        File file = new File(imgSrc);
        InputStream is = null;
        byte[] result = null;
        try {
            is = new FileInputStream(file);
            // 如果是MultipartFile类型，那么自身也有转换成流的方法：is = file.getInputStream();
            BufferedImage bi = ImageIO.read(is);
            Image image = (Image) bi;
            ImageIcon imageIcon = new ImageIcon(image);
            BufferedImage bufferedImage = new BufferedImage(imageIcon.getIconWidth(), imageIcon.getIconHeight(),
                    BufferedImage.TYPE_4BYTE_ABGR);
            Graphics2D g2D = (Graphics2D) bufferedImage.getGraphics();
            g2D.drawImage(imageIcon.getImage(), 0, 0, imageIcon.getImageObserver());
            int alpha = 0;
            for (int j1 = bufferedImage.getMinY(); j1 < bufferedImage.getHeight(); j1++) {
                for (int j2 = bufferedImage.getMinX(); j2 < bufferedImage.getWidth(); j2++) {
                    int rgb = bufferedImage.getRGB(j2, j1);

                    int R = (rgb & 0xff0000) >> 16;
                    int G = (rgb & 0xff00) >> 8;
                    int B = (rgb & 0xff);
                    if (((255 - R) < 30) && ((255 - G) < 30) && ((255 - B) < 30)) {
                        rgb = ((alpha + 1) << 24) | (rgb & 0x00ffffff);
                    }

                    bufferedImage.setRGB(j2, j1, rgb);

                }
            }

            g2D.drawImage(bufferedImage, 0, 0, imageIcon.getImageObserver());
            byteArrayOutputStream = new ByteArrayOutputStream();
            ImageIO.write(bufferedImage, "png", byteArrayOutputStream);//转换成byte数组
            result = byteArrayOutputStream.toByteArray();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (is != null) {
                try {
                    is.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                }
            }
            if (byteArrayOutputStream != null) {
                try {
                    byteArrayOutputStream.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                }
            }
        }
        return result;
    }

}

 

3.添加印章的工具类

 

package lucky.aozhan.user.utils;

import com.itextpdf.text.DocumentException;
import com.itextpdf.text.Image;
import com.itextpdf.text.pdf.PdfContentByte;
import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.text.pdf.PdfStamper;
import com.itextpdf.text.pdf.parser.ImageRenderInfo;
import com.itextpdf.text.pdf.parser.PdfReaderContentParser;
import com.itextpdf.text.pdf.parser.RenderListener;
import com.itextpdf.text.pdf.parser.TextRenderInfo;

import java.awt.geom.Rectangle2D;
import java.io.FileOutputStream;
import java.io.IOException;

public class AddYingZhangImgUtil {
    public static void main(String[] args) throws IOException, DocumentException {
        // 模板文件路径
        String templatePath = "D:\\resource\\yinzhang\\p869.pdf";
        // 生成的文件路径
        String targetPath = "D:\\resource\\yinzhang\\p869_new.pdf";
        // 图片路径, 需要png透明图片,否则会覆盖文字
        String imagePath = "D:\\resource\\yinzhang\\aozhanyzimg_1.png";

        addSignImg(templatePath, targetPath, imagePath, "INSPECTION", null);

    }

    /**
     * 根据pdf中的关键字，获取文字的绝对位置，并进行签章
     *
     * @param inputPath  未处理pdf
     * @param targetPath 已签章pdf地址
     * @param imagePath  签章图片地址
     * @param inputPath  pdf中的关键字
     * @param pageNum    pdf页数,可传null，默认设置最大页数
     * @return float的x与y值
     * @throws IOException
     */
    private static void addSignImg(String inputPath, String targetPath, final String imagePath, final String keyWord, Integer pageNum) throws IOException, DocumentException {
        PdfReader pdfReader = new PdfReader(inputPath);
        // 读图片
        final Image image = Image.getInstance(imagePath);
        // 根据域的大小缩放图片
        image.scaleToFit(100, 100);
        image.setRotationDegrees(15);//设置印章图片的旋转角度

        if (null == pageNum) {
            pageNum = pdfReader.getNumberOfPages();
        }
        new PdfReaderContentParser(pdfReader).processContent(pageNum, new RenderListener() {
            public void beginTextBlock() {

            }

            public void renderText(TextRenderInfo textRenderInfo) {
                String text = textRenderInfo.getText();
                if (text != null && text.contains(keyWord)) {
                    // 文字在page中的横坐标、纵坐标
                    com.itextpdf.awt.geom.Rectangle2D.Float textFloat = textRenderInfo.getBaseline().getBoundingRectange();
                    float x = textFloat.x;
                    float y = textFloat.y;
                    // 设置图片位置
                    image.setAbsolutePosition(x + 50f, y - 30f);
                }
            }

            public void endTextBlock() {

            }

            public void renderImage(ImageRenderInfo renderInfo) {

            }
        });
        // 获取操作的页面
        PdfStamper stamper = new PdfStamper(pdfReader, new FileOutputStream(targetPath));
        PdfContentByte under = stamper.getOverContent(pageNum);
        under.addImage(image);
        stamper.close();
        pdfReader.close();
    }
}

 

4.效果图

 

参考文献：

https://blog.csdn.net/weixin_39515661/article/details/90402601?depth_1-utm_source=distribute.pc_relevant.none-task&utm_source=distribute.pc_relevant.none-task