Java 操作PDF图片合并、PDF图片互转

2023-6-23

导入所需依赖jar坐标

<dependencies>
        <!-- https://mvnrepository.com/artifact/com.itextpdf/itextpdf -->
        <dependency>
            <groupId>com.itextpdf</groupId>
            <artifactId>itextpdf</artifactId>
            <version>5.5.13</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.apache.pdfbox/pdfbox -->
        <dependency>
            <groupId>org.apache.pdfbox</groupId>
            <artifactId>pdfbox</artifactId>
            <version>2.0.24</version>
        </dependency>
    </dependencies>

PDF与图片合并

public class Main {
    public static void main(String[] args) throws IOException, DocumentException {
        // 读入PDF文档
        File file = new File("a.pdf");
        // 合成后的PDF文档
        FileOutputStream outputStream = new FileOutputStream("c.pdf");
        PdfReader reader = new PdfReader(new FileInputStream(file));
        PdfStamper stamper = new PdfStamper(reader, outputStream);
        // 将签名图片放在pdf文件的第2页
        PdfContentByte over = stamper.getOverContent(2);
        // 签名图片
        Image contractSealImg = Image.getInstance("c.png");
        over.saveState();
        PdfGState pdfGState = new PdfGState();
        // 设置图片的透明度
        // pdfGState.setFillOpacity(0.8F);
        over.setGState(pdfGState);
        // 设置图片位置
        contractSealImg.setAbsolutePosition(480,650);
        // 设置图片大小
        contractSealImg.scaleAbsolute(80, 60);
        // 将图片添加到PDF文档
        over.addImage(contractSealImg);
        over.restoreState();
        stamper.setFormFlattening(true);
        stamper.close();
        reader.close();
        outputStream.close();
    }
}

PDF转换成图片

public class PDF2PNG {
    public static void main(String[] args) {
        try {
            // 加载PDF文件
            PDDocument document = PDDocument.load(new File("c.pdf"));
            // 创建PDFRenderer对象
            PDFRenderer renderer = new PDFRenderer(document);
            // 获取PDF文件的页数
            int pageCount = document.getNumberOfPages();
            // 循环处理每一页
            for (int i = 0; i < pageCount; i++) {
                // 渲染当前页为图像
                BufferedImage image = renderer.renderImage(i);
                // 将图像保存为PNG文件
                ImageIO.write(image, "PNG", new File("output" + i + ".png"));
            }
            // 关闭PDF文件
            document.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

图片转换PDF

public class ImgToPdfUtil {
    public static File Pdf(ArrayList<String> imageUrllist, String mOutputPdfFileName) {
        // new一个新的PDF文档
        Document doc = new Document(PageSize.A4, 0, 0, 0, 0);
        try {
            // pdf写入
            PdfWriter.getInstance(doc, new FileOutputStream(mOutputPdfFileName));
            // 打开文档
            doc.open();
            // 循环图片List，将图片加入到pdf中
            for (int i = 0; i < imageUrllist.size(); i++) {
                // 在pdf创建一页
                doc.newPage();
                // 通过文件路径获取image
                Image png1 = Image.getInstance(imageUrllist.get(i));
                float heigth = png1.getHeight();
                float width = png1.getWidth();
                int percent = getPercent2(heigth, width);
                png1.setAlignment(Image.MIDDLE);
                // 表示是原来图像的比例;
                png1.scalePercent(percent + 3);
                doc.add(png1);
            }
            doc.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (DocumentException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        // 输出流
        File mOutputPdfFile = new File(mOutputPdfFileName);
        if (!mOutputPdfFile.exists()) {
            mOutputPdfFile.deleteOnExit();
            return null;
        }
        // 反回文件输出流
        return mOutputPdfFile;
    }

    public static int getPercent(float h, float w) {
        int p = 0;
        float p2 = 0.0f;
        if (h > w) {
            p2 = 297 / h * 100;
        } else {
            p2 = 210 / w * 100;
        }
        p = Math.round(p2);
        return p;
    }

    public static int getPercent2(float h, float w) {
        int p = 0;
        float p2 = 0.0f;
        p2 = 530 / w * 100;
        p = Math.round(p2);
        return p;
    }

    public void imgOfPdf(String filepath, String imgUrl) {
        try {
            // 图片list集合
            ArrayList<String> imageUrllist = new ArrayList<String>();
            String[] imgUrls = imgUrl.split(",");
            for (int i=0; i<imgUrls.length; i++) {
                imageUrllist.add(imgUrls[i]);
            }
            // 输出pdf文件路径
            String pdfUrl =  filepath;
            // 生成pdf
            File file = Pdf(imageUrllist, pdfUrl);
            file.createNewFile();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        ImgToPdfUtil img = new ImgToPdfUtil();
        img.imgOfPdf("hkxx.pdf","hkxx.png");
    }
}