How to use java to realize the functions of file upload, download and picture preview
Editor to share with you how to use java to achieve file upload, download, picture preview functions, I believe that most people do not understand, so share this article for your reference, I hope you can learn a lot after reading this article, let's go to know it!
Save multiple files locally:
@ ResponseBody @ RequestMapping (value = "/ uploadApp", produces = {"application/json;charset=UTF-8"}, method= RequestMethod.POST) public String uploadApp (HttpServletRequest request,@RequestParam ("file") MultipartFile [] file) throws IOException {try {if (file.length > 0) {String name = file [0] .getOriginalFilename (). Split (";") [0]; String fileUrlName = CommonEnum.FILEPATH+ "/" + name; for (int I = 0; I
< file.length; i++) { FileUtils.copyInputStreamToFile(file[i].getInputStream(), new File(fileUrlName, file[i].getOriginalFilename().split(";")[1])); } return "success"; }else{ return "null"; } }catch (Exception e){ e.printStackTrace(); return "error"; } } 下载文件： @RequestMapping(value = "/download", method = RequestMethod.GET) @ResponseBody public void download(@RequestParam Map data, HttpServletRequest request,HttpServletResponse response) throws FileNotFoundException { String time = DateUtil.formatFromDate("yyyyMMddHHmmss", new Date()); List urllist = companyService.findByIMG(data); String path = (String) urllist.get(0).get("imgurl"); String docx = StringUtils.substringAfterLast(path, "."); String fileName = time+"."+docx; // 文件的默认保存名 InputStream inStream = new FileInputStream(path);// 文件的存放路径 response.reset(); response.setContentType("bin"); response.addHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\""); byte[] b = new byte[100]; int len; try { while ((len = inStream.read(b)) >0) response.getOutputStream (). Write (b, 0, len); inStream.close ();} catch (IOException e) {e.printStackTrace ();}} / * * read pictures * / @ RequestMapping (value = "/ iomoreimgcom", produces = {"application/json;charset=UTF-8"}, method = RequestMethod.GET) @ ResponseBody public synchronized void iomoreimgcom (HttpServletRequest request, HttpServletResponse response) throws Exception {String url = request.getParameter ("url"); File file = new File (url) BufferedInputStream bis = new BufferedInputStream (new FileInputStream (file)); BufferedOutputStream bos = new BufferedOutputStream (response.getOutputStream ()); response.setHeader ("Content-Type", "image/jpeg"); byte b [] = new byte [1024]; int read; try {while ((read = bis.read (b))! =-1) {bos.write (b, 0, read);} / / request.getRequestDispatcher ("/ components/hazard/yscchird.html") .forward (request, response) } catch (Exception e) {/ / TODO: handle exception} finally {if (bos! = null) {bos.close ();} if (bis! = null) {bis.close ();}
The frontend request is to stitch the image path directly.
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