关于pdf:pdf转图片

 <dependency>            <groupId>org.apache.pdfbox</groupId>            <artifactId>pdfbox</artifactId>            <version>2.0.18</version>        </dependency>        <dependency>            <groupId>org.apache.pdfbox</groupId>            <artifactId>jbig2-imageio</artifactId>            <version>3.0.2</version>        </dependency>        <dependency>            <groupId>org.apache.pdfbox</groupId>            <artifactId>pdfbox-tools</artifactId>            <version>2.0.18</version>        </dependency>

@Test    public void pdf2image2() throws IOException {        PDDocument pdDocument;        FileInputStream fileInputStream = new FileInputStream("d:/test.pdf");        pdDocument = PDDocument.load(fileInputStream);        PDFRenderer renderer = new PDFRenderer(pdDocument);        // 获取PDF页数        int pages = pdDocument.getNumberOfPages();        for (int i = 0; i < pages; i++) {            BufferedImage image = renderer.renderImage(i, 2.5f, ImageType.BINARY, RenderDestination.PRINT);            FileOutputStream out = new FileOutputStream("d:\\imageresult" + i + ".png");            // PNG            ImageIO.write(image, "png", out);        }        pdDocument.close();    }

应用renderImage会小很多

aspose

  FileInputStream fileInputStream = new FileInputStream("D:\\test.pdf");        Document pdfDocument = new Document(fileInputStream);        Resolution resolution = new Resolution(72);        JpegDevice jpegDevice = new JpegDevice(740, 1046, resolution, 100);        RenderingOptions renderingOptions = new RenderingOptions();        for (int index = 1; index <= pdfDocument.getPages().size(); index++) {            // 输入门路            FileOutputStream out = new FileOutputStream("d:\\image" + index + ".jpg");            jpegDevice.process(pdfDocument.getPages().get_Item(index), out);            out.close();        }        pdfDocument.close();

图片压缩

 File imageFile = new File("d:\\imageresult0.jpg");        File compressedImageFile = new File("d:\\myimage_compressed.jpg");        InputStream is = new FileInputStream(imageFile);        OutputStream os = new FileOutputStream(compressedImageFile);        float quality = 0.01f;        // create a BufferedImage as the result of decoding the supplied InputStream        BufferedImage image = ImageIO.read(is);        // get all image writers for JPG format        Iterator<ImageWriter> writers = ImageIO.getImageWritersByFormatName("jpg");        if (!writers.hasNext())            throw new IllegalStateException("No writers found");        ImageWriter writer = (ImageWriter) writers.next();        ImageOutputStream ios = ImageIO.createImageOutputStream(os);        writer.setOutput(ios);        ImageWriteParam param = writer.getDefaultWriteParam();        param.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);        param.setCompressionQuality(quality);        writer.write(null, new IIOImage(image, null, null), param);        // close all streams        is.close();        os.close();        ios.close();        writer.dispose();