文件上传下载

单文件上传

<form action="/layui/upload" method="POST" enctype="multipart/form-data">
    文件：<input type="file" name="file"/>
    <input type="submit"/>
</form>

  @PostMapping(value = "upload")
    @ResponseBody
    public Map upload(@RequestParam("file") MultipartFile file) {
        Map map=new HashMap();
        try {
            if (file.isEmpty()) {
                map.put("msg","文件为空");
                return map;
            }
            // 获取文件名
            String fileName = file.getOriginalFilename();
            log.info("上传的文件名为：" + fileName);
            // 获取文件的后缀名
            String suffixName = fileName.substring(fileName.lastIndexOf("."));
            log.info("文件的后缀名为：" + suffixName);
            // 设置文件存储路径
            String filePath = "D:/测试文件上传下载功能/";
            String path = filePath + fileName;
            File dest = new File(path);
            // 检测是否存在目录
            if (!dest.getParentFile().exists()) {
                dest.getParentFile().mkdirs();// 新建文件夹
            }
            file.transferTo(dest);// 文件写入
            map.put("msg","上传成功");
            return map;
        }
        catch (IllegalStateException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        map.put("msg","上传失败");
        return map;
    }

 多文件上传

<p>多文件上传</p>
<form method="POST" enctype="multipart/form-data" action="/layui/batch">
    <p>文件1：<input type="file" name="file"/></p>
    <p>文件2：<input type="file" name="file"/></p>
    <p><input type="submit" value="上传"/></p>
</form>

 @PostMapping("batch")
    @ResponseBody
    public String handleFileUpload(HttpServletRequest request) {
        List<MultipartFile> files = ((MultipartHttpServletRequest) request).getFiles("file");
        MultipartFile file = null;
        BufferedOutputStream stream = null;
        for (int i = 0; i < files.size(); ++i) {
            file = files.get(i);
            String filePath = "D:/测试文件上传下载功能/";
            if (!file.isEmpty()) {
                try {
                    byte[] bytes = file.getBytes();
                    stream = new BufferedOutputStream(new FileOutputStream(
                            new File(filePath + file.getOriginalFilename())));//设置文件路径及名字
                    stream.write(bytes);// 写入
                    stream.close();
                } catch (Exception e) {
                    stream = null;
                    return "第 " + i + " 个文件上传失败 ==> "
                            + e.getMessage();
                }
            } else {
                return "第 " + i
                        + " 个文件上传失败因为文件为空";
            }
        }
        return "上传成功";
    }

文件下载

<p>文件下载</p>
<a href="/layui/download">下载文件</a>

 @GetMapping("download")
    @ResponseBody
    public String downloadFile(HttpServletRequest request, HttpServletResponse response) {
        String fileName = "交接内容.xlsx";// 文件名
        if (fileName != null) {
            //设置文件路径
            File file = new File("C:/Users/fanyx/Desktop/交接内容.xlsx");
            //File file = new File(realPath , fileName);
            if (file.exists()) {

                byte[] buffer = new byte[1024];
                FileInputStream fis = null;
                BufferedInputStream bis = null;
                try {
                    response.setContentType("application/force-download");// 设置强制下载不打开
                    response.addHeader("Content-Disposition", "attachment;fileName=" + new String(fileName.getBytes("UTF-8"),"ISO8859-1"));// 设置文件名
                    fis = new FileInputStream(file);
                    bis = new BufferedInputStream(fis);
                    OutputStream os = response.getOutputStream();
                    int i = bis.read(buffer);
                    while (i != -1) {
                        os.write(buffer, 0, i);
                        i = bis.read(buffer);
                    }
                    return "下载成功";
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    if (bis != null) {
                        try {
                            bis.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                    if (fis != null) {
                        try {
                            fis.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }
            }
        }
        return "下载失败";
    }