SpringBoot实现PPT格式文件上传并在线预览功能
作者:Just do Java
本文介绍SpringBoot实现PPT格式文件上传并在线预览功能,通过上传接口,可在C盘的tempfile目录下找到上传的文件,预览时会在同级目录下创建一个相同文件名后缀为pdf的文件,每次预览会先查找文件是否存在,存在则直接预览,不存在则会走上面的处理,需要的朋友可以参考下
1、需要引入依赖
<dependency> <groupId>com.itextpdf</groupId> <artifactId>itextpdf</artifactId> <version>5.5.9</version> </dependency> <dependency> <groupId>org.apache.poi</groupId> <artifactId>poi</artifactId> <version>3.15</version> </dependency> <dependency> <groupId>org.apache.poi</groupId> <artifactId>poi-ooxml</artifactId> <version>3.15</version> </dependency> <!--其他格式转换为PDF --> <dependency> <groupId>fr.opensagres.xdocreport</groupId> <artifactId>xdocreport</artifactId> <version>1.0.6</version> </dependency> <dependency> <groupId>commons-io</groupId> <artifactId>commons-io</artifactId> <version>2.11.0</version> </dependency>
2、上传文件到本地文件夹中
@PostMapping(value = "/upload", consumes = MediaType.MULTIPART_FORM_DATA_VALUE) public ResponseEntity<Object> uploadFileToLocal(@RequestParam("multipartFile") MultipartFile multipartFile) { if (multipartFile == null) { return ResponseEntity.status(HttpStatus.NO_CONTENT).build(); } File file = null; try { File dir = new File(basePath); if (!dir.exists()) { dir.mkdir(); } file = new File(basePath + File.separator + multipartFile.getOriginalFilename()); if (!file.exists()) { multipartFile.transferTo(file); } } catch (IOException e) { e.printStackTrace(); } return ResponseEntity.ok(FileVo.builder().size(multipartFile.getSize()).path(file.getAbsolutePath()).build()); }
basePath为定义的常量: private static final String basePath = “C:\tempFile”;
通过上传接口,可在C盘的tempfile目录下找到上传的文件,首先我们先上传一个PPT文件,上传成功会返回文件的绝对路径地址以及文件大小,绝对地址将作为在线预览文件接口的参数。
3、在线预览PPT文件
@GetMapping("/showPPT") public void showPPT(@RequestParam("path") String path,HttpServletResponse response) throws IOException { byte[] buffer = new byte[1024 * 4]; String type = path.substring(path.lastIndexOf(".") + 1); //转换pdf文件,如存在则直接显示pdf文件 String pdf = path.replace(type, "pdf"); File pdfFile = new File(pdf); if (pdfFile.exists()) { outFile(buffer, pdfFile, response); } else { FileInputStream in = new FileInputStream(path); ZipSecureFile.setMinInflateRatio(-1.0d); XMLSlideShow xmlSlideShow = new XMLSlideShow(in); in.close(); // 获取大小 Dimension pgsize = xmlSlideShow.getPageSize(); // 获取幻灯片 List<XSLFSlide> slides = xmlSlideShow.getSlides(); List<File> imageList = new ArrayList<>(); for (int i = 0; i < slides.size(); i++) { // 解决乱码问题 List<XSLFShape> shapes = slides.get(i).getShapes(); for (XSLFShape shape : shapes) { if (shape instanceof XSLFTextShape) { XSLFTextShape sh = (XSLFTextShape) shape; List<XSLFTextParagraph> textParagraphs = sh.getTextParagraphs(); for (XSLFTextParagraph xslfTextParagraph : textParagraphs) { List<XSLFTextRun> textRuns = xslfTextParagraph.getTextRuns(); for (XSLFTextRun xslfTextRun : textRuns) { xslfTextRun.setFontFamily("宋体"); } } } } //根据幻灯片大小生成图片 BufferedImage img = new BufferedImage(pgsize.width, pgsize.height, BufferedImage.TYPE_INT_RGB); Graphics2D graphics = img.createGraphics(); graphics.setPaint(Color.white); graphics.fill(new Rectangle2D.Float(0, 0, pgsize.width, pgsize.height)); // 将PPT内容绘制到img上 slides.get(i).draw(graphics); //图片将要存放的路径 String absolutePath = basePath + File.separator+ (i + 1) + ".jpg"; File jpegFile = new File(absolutePath); if (!jpegFile.exists()) { // 判断如果图片存在则不再重复创建,建议将图片存放到一个特定目录,后面会统一删除 FileOutputStream fileOutputStream = new FileOutputStream(jpegFile); ImageIO.write(img, "jpg", fileOutputStream); } // 图片路径存放 imageList.add(jpegFile); } File file = png2Pdf(imageList, pdf); outFile(buffer, file, response); } } private void outFile(byte[] buffer, File pdfFile, HttpServletResponse response) throws IOException { ByteArrayOutputStream out; int n = 0; FileInputStream fileInputStream = new FileInputStream(pdfFile); out = new ByteArrayOutputStream(); ServletOutputStream outputStream = response.getOutputStream(); while ((n = fileInputStream.read(buffer)) != -1) { out.write(buffer, 0, n); } outputStream.write(out.toByteArray()); outputStream.flush(); } //将图片列表转换为PDF格式文件并存储 public File png2Pdf(List<File> pngFiles, String pdfFilePath) { Document document = new Document(); File pdfFile = null; long startTime = System.currentTimeMillis(); try { pdfFile = new File(pdfFilePath); if (pdfFile.exists()) { return pdfFile; } PdfWriter.getInstance(document, new FileOutputStream(pdfFile)); document.open(); pngFiles.forEach(pngFile -> { try { Image png = Image.getInstance(pngFile.getCanonicalPath()); png.scalePercent(50); document.add(png); } catch (Exception e) { System.out.println("png2Pdf exception"); } }); document.close(); return pdfFile; } catch (Exception e) { System.out.println(String.format("png2Pdf %s exception", pdfFilePath)); } finally { if (document.isOpen()) { document.close(); } // 删除临时生成的png图片 for (File pngFile : pngFiles) { try { FileUtils.delete(pngFile); } catch (IOException e) { e.printStackTrace(); } } long endTime = System.currentTimeMillis(); System.out.println("png2Pdf耗时:" + (endTime - startTime)); } return null; }
核心思路:将PPT文件读取每一页幻灯片,将幻灯片转换为图片格式,最后将所有图片放到一个pdf文件中形成一个pdf文件用于在线预览。预览时会在同级目录下创建一个相同文件名后缀为pdf的文件,每次预览会先查找文件是否存在,存在则直接预览,不存在则会走上面的处理。
4、预览效果
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