@Data
@AllArgsConstructor
public class Files {
    private String name;
    private String url;
}

public interface FilesService {
    public void init();

    public void save(MultipartFile file);

    public Resource load(String filename);

    public void deleteAll();

    public Stream<Path> loadAll();
}

Service
public class FilesServiceImpl implements FilesService {

    private final Path root = Paths.get("uploads");

    @Override
    public void init() {
        try {
            Files.createDirectory(root);
        } catch (IOException e) {
            throw new RuntimeException("Could not initialize folder for upload!");
        }
    }

    @Override
    public void save(MultipartFile file) {
        try {
            Files.copy(file.getInputStream(), this.root.resolve(file.getOriginalFilename()));
        } catch (Exception e) {
            throw new RuntimeException("Could not store the file. Error: " + e.getMessage());
        }
    }

    @Override
    public Resource load(String filename) {
        try {
            Path file = root.resolve(filename);
            Resource resource = new UrlResource(file.toUri());

            if (resource.exists() || resource.isReadable()) {
                return resource;
            } else {
                throw new RuntimeException("Could not read the file!");
            }
        } catch (MalformedURLException e) {
            throw new RuntimeException("Error: " + e.getMessage());
        }
    }

    @Override
    public void deleteAll() {
        FileSystemUtils.deleteRecursively(root.toFile());
    }

    @Override
    public Stream<Path> loadAll() {
        try {
            return Files.walk(this.root, 1).filter(path -> !path.equals(this.root)).map(this.root::relativize);
        } catch (IOException e) {
            throw new RuntimeException("Could not load the files!");
        }
    }
}

@RestController
public class FilesController {

    @Autowired
    FilesService storageService;

    @PostMapping("/upload")
    public ResponseEntity<FilesResponseMessage> uploadFile(@RequestParam("file") MultipartFile file) {
        String message = "";
        try {
            storageService.save(file);

            message = "Uploaded the file successfully: " + file.getOriginalFilename();
            return ResponseEntity.status(HttpStatus.OK).body(new FilesResponseMessage(message));
        } catch (Exception e) {
            message = "Could not upload the file: " + file.getOriginalFilename() + "!";
            return ResponseEntity.status(HttpStatus.EXPECTATION_FAILED).body(new FilesResponseMessage(message));
        }
    }

    @GetMapping("/files")
    public ResponseEntity<List<Files>> getListFiles() {
        List<Files> fileInfos = storageService.loadAll().map(path -> {
            String filename = path.getFileName().toString();
            String url = MvcUriComponentsBuilder
                    .fromMethodName(FilesController.class, "getFile", path.getFileName().toString()).build().toString();

            return new Files(filename, url);
        }).collect(Collectors.toList());

        return ResponseEntity.status(HttpStatus.OK).body(fileInfos);
    }

    @GetMapping("/files/{filename:.+}")
    @ResponseBody
    public ResponseEntity<Resource> getFile(@PathVariable String filename) {
        Resource file = storageService.load(filename);
        return ResponseEntity.ok()
                .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + file.getFilename() + "\"").body(file);
    }
}

@RestControllerAdvice
public class FilesControllerExceptionHandler extends ResponseEntityExceptionHandler {

    @ExceptionHandler(MaxUploadSizeExceededException.class)
    public ResponseEntity<FilesResponseMessage> handleMaxSizeException(MaxUploadSizeExceededException exc) {
        return ResponseEntity.status(HttpStatus.EXPECTATION_FAILED).body(new FilesResponseMessage("File too large!"));
    }
}

@Data
@AllArgsConstructor
public class FilesResponseMessage {
    private String message;
}

@SpringBootApplication
public class Demo12Application implements CommandLineRunner {


	public static void main(String[] args) {


        SpringApplication.run(Demo12Application.class, args);
	}




    @Autowired
    FileService storageService;


    @Override
    public void run(String... arg) throws Exception {
        storageService.deleteAll();
        storageService.init();
    }



}

spring.servlet.multipart.max-file-size=500KB
spring.servlet.multipart.max-request-size=500KB