java文件上传、下载、图片预览

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<String, Object> data, HttpServletRequest request,HttpServletResponse response) throws FileNotFoundException {
        String time = DateUtil.formatFromDate("yyyyMMddHHmmss", new Date());
        List<Map<String, Object>> 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。