[JavaWeb] SpringBoot上传文件

@PostMapping("/upload_file")
    public Map<String, Object> uploadFile(
            @RequestParam(value = "upload_file", required = false) MultipartFile uploadFile
    ) {
        Map<String, Object> resultJson = new LinkedHashMap<>();
        if (uploadFile == null || uploadFile.isEmpty()) {
            resultJson.put("code", -1);
            resultJson.put("msg", "上传文件不得为空");
            return resultJson;
        }
        String originalFilename = uploadFile.getOriginalFilename(); // 上传的文件原名称
        String suffix = originalFilename.substring(originalFilename.lastIndexOf(".") + 1) ; // 取后缀名

        String newFileName = DigestUtils.md5DigestAsHex((System.currentTimeMillis() + originalFilename).getBytes()) + "." + suffix; // 新的文件名
        try {
            String fileRootPath = ResourceUtils.getURL("classpath:").getPath() + "/public/"; // 取项目的 classpath目录的绝对路径下的 public文件夹下
            String filePath = fileRootPath + "/upload/" + newFileName;

            File file1 = new File(filePath);
            if (!file1.exists()) file1.mkdirs(); // 要是目录不存在,创建一个
            uploadFile.transferTo(file1); // 保存起来

            resultJson.put("code", 1);
            resultJson.put("data", "/upload/" + newFileName);
            resultJson.put("msg", "保存成功");
        }catch (Exception e) {
            e.printStackTrace();
            resultJson.put("code", 0);
            resultJson.put("msg", e.getMessage());
        }
        return resultJson;
    }