<form action="uploadFile" method="post" enctype="multipart/form-data"><p>选择文件: <input type="file" name="fileName"/></p><p><input type="submit" value="提交"/></p></form>

    @RequestMapping("/uploadFile")@ResponseBodypublic String uploadFile(@RequestParam("fileName") MultipartFile file) {//判断文件是否为空if (file.isEmpty()) {return "-1";}String fileName = file.getOriginalFilename();//加个时间戳，尽量避免文件名称重复String path = "D:/" + new SimpleDateFormat("yyyyMMddHHmmss").format(new Date()) + "_" + fileName;File dest = new File(path);//判断文件是否已经存在if (dest.exists()) {return "-2";}//判断文件父目录是否存在if (!dest.getParentFile().exists()) {dest.getParentFile().mkdir();}try {file.transferTo(dest); //保存文件} catch (IOException e) {return "-3";}return "0";}

    <form action="uploadMultifile" method="post" enctype="multipart/form-data" ><p>选择文件1: <input type="file" name="fileName"/></p><p>选择文件2: <input type="file" name="fileName"/></p><p>选择文件3: <input type="file" name="fileName"/></p><p><input type="submit" value="提交"/></p></form>

    @RequestMapping("/uploadMultifile")@ResponseBodypublic String keywordSubmitFile(@RequestParam("fileName") List<MultipartFile> files) {for (MultipartFile file : files) {//这里简单输出文件名称
            System.out.println(file.getOriginalFilename());}return "0";}

@RequestMapping("/downloadFile") @ResponseBodypublic String downloadFile(HttpServletResponse response, @RequestParam("fileName") String filePathName) {File file = new File(filePathName);if (!file.exists()) {return "-1";}response.reset();response.setHeader("Content-Disposition", "attachment;fileName=" + filePathName);try {InputStream inStream = new FileInputStream(filePathName);OutputStream os = response.getOutputStream();byte[] buff = new byte[1024];int len = -1;while ((len = inStream.read(buff)) > 0) {os.write(buff, 0, len);}os.flush();os.close();inStream.close();} catch (Exception e) {e.printStackTrace();return "-2";}return "0";}

spring.servlet.multipart.maxFileSize=30MB
spring.servlet.multipart.maxRequestSize=30MB

spring.servlet.multipart.maxFileSize=-1
spring.servlet.multipart.maxRequestSize=-1