在项目有上传pdf的需求,然而上传完图片可以在页面上通过img显示上传的图片,于是就想到通过img显示pdf的首页当作预览吧,点击图片再打开新窗口显示完整pdf文件或者直接下载。
pdf-renderer可以实现此需求
@RequestMapping(value = "/pdf")
public void pdfrender(HttpServletResponse response) throws IOException {
int pagen = 0;
File file = new File("E:/pan/example.pdf");
InputStream inputStream = new FileInputStream(file);
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
StreamUtils.copy(inputStream, byteArrayOutputStream);
ByteBuffer buf = ByteBuffer.wrap(byteArrayOutputStream.toByteArray());
PDFFile pdffile = new PDFFile(buf);
PDFPage page = pdffile.getPage(pagen);
int width = (int) page.getBBox().getWidth();
int height = (int) page.getBBox().getHeight();
Rectangle rect = new Rectangle(0, 0, width, height);
BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics2D bufImageGraphics = bufferedImage.createGraphics();
Image image = page.getImage(width, height, rect, null, true, true);
bufImageGraphics.drawImage(image, 0, 0, null);
ImageIO.write(bufferedImage, "jpg", response.getOutputStream());
}
此方法是基于spring框架写的,其中StreamUtils也是spring中的方法
上面方法的pdf文件是以File类型拿到的,如果拿到的就是InputStream,则可跳过FileInputStream转换的过程,如果以其它形式拿到,则先做相应的转化即可。