java - 文件未保存到目录中

Question

我想使用此代码将文件上传到 Spring 后端。

private static String UPLOADED_FOLDER = "/opt";

    @PostMapping(value = "/upload", produces = { MediaType.APPLICATION_JSON_VALUE })
    public ResponseEntity<StringResponseDTO> uploadData(@RequestParam("file") MultipartFile file, RedirectAttributes redirectAttributes) throws Exception {

        if (file == null) {
            throw new RuntimeException("You must select the a file for uploading");
        }

        InputStream inputStream = file.getInputStream();
        String originalName = file.getOriginalFilename();
        String name = file.getName();
        String contentType = file.getContentType();
        long size = file.getSize();

        LOG.info("inputStream: " + inputStream);
        LOG.info("originalName: " + originalName);
        LOG.info("name: " + name);
        LOG.info("contentType: " + contentType);
        LOG.info("size: " + size);

        try {

            // Get the file and save it somewhere
            byte[] bytes = file.getBytes();
            Path path = Paths.get(UPLOADED_FOLDER + file.getOriginalFilename());
            Files.write(path, bytes);

            redirectAttributes.addFlashAttribute("message",
                    "You successfully uploaded '" + file.getOriginalFilename() + "'");

        } catch (IOException e) {
            e.printStackTrace();
        }

        return ResponseEntity.ok(new StringResponseDTO(originalName));
    }

由于某种原因，该文件未保存到/opt 目录中。您能给我一些关于代码不起作用的建议吗？

进入我得到的日志文件:

2019-08-11 20:40:36,297 INFO  [stdout] (default task-17) 20:40:36.297 [default task-17] INFO  o.d.a.b.restapi.MerchantController - inputStream: java.io.BufferedInputStream@661c793f
2019-08-11 20:40:36,298 INFO  [stdout] (default task-17) 20:40:36.298 [default task-17] INFO  o.d.a.b.restapi.MerchantController - originalName: Screenshot 2019-07-14 at 14.33.41.png
2019-08-11 20:40:36,299 INFO  [stdout] (default task-17) 20:40:36.298 [default task-17] INFO  o.d.a.b.restapi.MerchantController - name: file
2019-08-11 20:40:36,299 INFO  [stdout] (default task-17) 20:40:36.299 [default task-17] INFO  o.d.a.b.restapi.MerchantController - contentType: image/png
2019-08-11 20:40:36,300 INFO  [stdout] (default task-17) 20:40:36.300 [default task-17] INFO  o.d.a.b.restapi.MerchantController - size: 20936

Answer 1

尝试执行以下操作，而不是使用 Paths#get:

File newFile = new File(UPLOADED_FOLDER, file.getOriginalFileName());
LOG.info("New file location: " + newFile.getAbsolutePath()); //Log the path
Files.write(newFile.toPath(), bytes);

与其对一堆String使用+运算符来创建新文件的路径，最好使用java .io.File 构造函数。然后使用 toPath 方法来获取它。