java - 在Java中将PDF转换为缩略图

Question

谁能给我推荐一个免费的 Java 库，它可以转换 PDF 并从第一页创建缩略​​图 (PNG)。

谢谢。

Answer 1

你可以试试pdf-renderer它是一个纯 Java 解决方案。以下代码创建第一页的图像。

File pdfFile = new File("/path/to/pdf.pdf");
RandomAccessFile raf = new RandomAccessFile(pdfFile, "r");
FileChannel channel = raf.getChannel();
ByteBuffer buf = channel.map(FileChannel.MapMode.READ_ONLY, 0, channel.size());
PDFFile pdf = new PDFFile(buf);
PDFPage page = pdf.getPage(0);

// create the image
Rectangle rect = new Rectangle(0, 0, (int) page.getBBox().getWidth(),
                                 (int) page.getBBox().getHeight());
BufferedImage bufferedImage = new BufferedImage(rect.width, rect.height,
                                  BufferedImage.TYPE_INT_RGB);

Image image = page.getImage(rect.width, rect.height,    // width & height
                            rect,                       // clip rect
                            null,                       // null for the ImageObserver
                            true,                       // fill background with white
                            true                        // block until drawing is done
);
Graphics2D bufImageGraphics = bufferedImage.createGraphics();
bufImageGraphics.drawImage(image, 0, 0, null);
ImageIO.write(bufferedImage, format, new File( "/path/to/image.jpg" ));