如何使用java实现文件上传、下载、图片预览功能

小编给大家分享一下如何使用java实现文件上传、下载、图片预览功能，相信大部分人都还不怎么了解，因此分享这篇文章给大家参考一下，希望大家阅读完这篇文章后大有收获，下面让我们一起去了解一下吧！

多文件保存到本地：

@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(); } } /** * 读取图片 */ @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(); } } }

前端请求直接拼接图片路径即可。

以上是"如何使用java实现文件上传、下载、图片预览功能"这篇文章的所有内容，感谢各位的阅读！相信大家都有了一定的了解，希望分享的内容对大家有所帮助，如果还想学习更多知识，欢迎关注行业资讯频道！