Java实现PDF转图片-蒲公英云

Java实现PDF转图片

注意事项：转图片后需仔细核对，因PDF内的字体可能不是宋体等最常见字体，转图片后可能出现中文乱码现象，需要查看原PDF文件中对应字体，下载后安装在本地或服务器上。

需引入jar依赖

<dependency>
    <groupId>org.apache.pdfbox</groupId>
    <artifactId>pdfbox</artifactId>
    <version>2.0.11</version>
</dependency>

情景1：将PDF转成一页长图

public static BufferedImage pdfToImage(InputStream inputStream) {
        //图像合并使用参数
        int width = 0; // 总宽度
        int[] singleImgRGB; // 保存一张图片中的RGB数据
        int shiftHeight = 0;
        BufferedImage imageResult = null;//保存每张图片的像素值
        try {
            //利用PdfBox生成图像
            PDDocument pdDocument = PDDocument.load(inputStream);
            PDFTextStripper text = new PDFTextStripper();
            String text1 = text.getText(pdDocument);
            logger.info("读取PDF文字:" + text1);
            PDFRenderer renderer = new PDFRenderer(pdDocument);
            //循环每个页码
            for (int i = 0, len = pdDocument.getNumberOfPages(); i < len; i++) {
                //dpi参数越大，越清晰
                BufferedImage image = renderer.renderImageWithDPI(i, 300, ImageType.RGB);
                int imageHeight = image.getHeight();
                int imageWidth = image.getWidth();
                if (i == 0) {//计算高度和偏移量
                    width = imageWidth;//使用第一张图片宽度;
                    //保存每页图片的像素值
                    imageResult = new BufferedImage(width, imageHeight * len, BufferedImage.TYPE_INT_RGB);
                } else {
                    shiftHeight += imageHeight; // 计算偏移高度
                }
                singleImgRGB = image.getRGB(0, 0, width, imageHeight, null, 0, width);
                imageResult.setRGB(0, shiftHeight, width, imageHeight, singleImgRGB, 0, width); // 写入流中
            }
            pdDocument.close();
        } catch (Exception e) {
            logger.error(" 从PDF转换JPG格式异常!", e);
        }
        return imageResult;
    }
public static void main(String[] args) {
    InputStream inputStream = null;
    BufferedImage bufferedImage = null;
    String url = "";
    try {
        //pdf转img
        bufferedImage = PDFUtils.pdfToImage(new URL(url));
        ByteArrayOutputStream os = new ByteArrayOutputStream();
        ImageIO.write(bufferedImage, "png", os);
        inputStream = new ByteArrayInputStream(os.toByteArray());
    } catch (IOException e) {
        e.printStackTrace();
    }
}

得到流后就可以下载到本地或者转存其他空间

情景2：将PDF文件转为图片，一页PDF对应一张图片，最终将图片打成zip包

public static ByteArrayOutputStream pdfToZip(String fileUrl, String fileName) {
    ByteArrayOutputStream bos = null;
    try {
        DataInputStream inputStream = new DataInputStream(new URL(fileUrl).openStream());
        PDDocument pdDocument = PDDocument.load(inputStream);
        PDFRenderer renderer = new PDFRenderer(pdDocument);
        bos = new ByteArrayOutputStream();
        ZipOutputStream zos = new ZipOutputStream(bos);
        byte[] bytes = null;
        //循环每个页码,一页都不能缺，所以内部不try-catch
        for (int i = 0, len = pdDocument.getNumberOfPages(); i < len; i++) {
            BufferedImage image = renderer.renderImageWithDPI(i, 300);
            ByteArrayOutputStream temp = new ByteArrayOutputStream();
            ImageIO.write(image, "png", temp);
            zos.putNextEntry(new ZipEntry(fileName + i + ".png"));
            bytes = temp.toByteArray();
            zos.write(bytes, 0, bytes.length);
            zos.closeEntry();
            temp.close();
        }
        zos.close();
        pdDocument.close();
    } catch (Exception e) {
        logger.error(" 从PDF转换PNG/ZIP格式异常!", e);
    }
    return bos;
}
public static void main(String[] args) {
    ByteArrayOutputStream os = pdfToZip(url, fileName);
    InputStream inputStream = new ByteArrayInputStream(os.toByteArray());
}