Java实现PDF转图片

旧城等待， 2022-04-24 04:30 343阅读 0赞

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());
>     }