springmvc之文件上传、下载

1、接收到的是图片的流时

//上传头像
    @RequestMapping(value = "/uploadHeadSculpture", method = RequestMethod.POST)
    @ResponseBody
    public String uploadHeadSculpture(@RequestParam("photo") String file) {
        User user = (User) SecurityUtils.getSubject().getSession().getAttribute("curr_user");
        //获取文件格式
        String postfix = file.split("/")[1].split(";")[0];
        //获取图片的Base64码
        String str = file.split(",")[1];
        String url = "";
        BASE64Decoder decoder = new BASE64Decoder();
        try {
            // Base64解码
            byte[] bytes = decoder.decodeBuffer(str);
            for (int i = 0; i < bytes.length; ++i) {
                // 调整异常数据
                if (bytes[i] < 0) {
                    bytes[i] += 256;
                }
            }
            long title = Calendar.getInstance().getTimeInMillis();
            //获取系统路径并设定文件保存的目录
            String dir = ServiceConfigUtil.getValue("imgpath");//图片的上传路径，我这里是从工程的配置文件获取的
            String fileName = title + "." + postfix;
            // 生成jpeg图片
            FileUtils.writeByteArrayToFile(new File(dir, fileName), bytes);
            String lookUserPhoto = ServiceConfigUtil.getValue("lookUserPhoto");//图片的访问路径，我这里是从工程配置文件获取的，可以自己定义。如果你的图片保存在工程目录下，可以直接用dir+fileName
            url = lookUserPhoto + fileName;//保存到数据库的图片访问路径
            /××
　　　　　　　　×保存url到数据库
　　　　　　　××/
        } catch (Exception e) {return "no";
        }return "yes";
    }

注：接收参数file值的一个基本格式

　　"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAIAAAACACAYAAADDPmHLAAAdiUlEQVR........."

2、接收到的是file文件直接上传

 @RequestMapping(value={"/saveOrUpdate"},method=RequestMethod.POST)
 public String saveOrUpdate(Person p, @RequestParam("photo") MultipartFile file, HttpServletRequest request) throws IOException{
     if(!file.isEmpty()){
        ServletContext sc = request.getSession().getServletContext();
         String dir = sc.getRealPath(“/upload”);    //设定文件保存的目录

        String filename = file.getOriginalFilename();    //得到上传时的文件名
        FileUtils.writeByteArrayToFile(new File(dir,filename), file.getBytes());

        p.setPhotoPath(“/upload/”+filename);    //设置图片所在路径

        System.out.println("upload over. "+ filename);
    }
    ps.saveOrUpdate(p);
    return "redirect:/person/list.action";   //重定向
}

2.1、页面

<form action="/saveOrUpdate" enctype="multipart/form-data" method="post">
    <input type="file" name="photo">
    <input type="submit" value="commit">
</form>

2.2、需要在springmvc配置文件中添加

<!--上传文件-->
    <bean id="multipartResolver"
          class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <property name="maxUploadSize" value="10000000000000"/>
        <property name="defaultEncoding" value="UTF-8"/>
    </bean>

3、文件下载

private void downFile(String filename, String realPath, HttpServletResponse response) throws IOException {
        try {
            filename = new String(filename.getBytes("ISO-8859-1"), "UTF-8");
        } catch (UnsupportedEncodingException e) {
            log.warn("文件转码出现异常异常信息为：" + ExceptionUtil.print(e));
        }
        log.debug("下载的文件名：" + filename);
        log.debug("下载的文件路径：" + realPath);
        OutputStream os = null;
        InputStream inputStream = null;
        try {
            response.setCharacterEncoding("utf-8");
            response.setContentType("multipart/form-data");
            response.setContentType("application/x-download");
            response.setHeader("Content-Disposition", "attachment;fileName="
                    + filename);
            inputStream = new FileInputStream(realPath);
            os = response.getOutputStream();
            byte[] b = new byte[1024];
            int length;
            while ((length = inputStream.read(b)) != -1) {
                os.write(b, 0, length);
            }
            os.flush();
        } catch (IOException e) {
            log.warn("下载文件出现异常，异常信息为：" + ExceptionUtil.print(e));
        } finally {
            inputStream.close();
            os.close();
        }
    }

参考：springmvc文件上传

数据导出：java 导出excel到客户端（本地）例子 用poi和servlet实现的