spring.servlet.multipart.max-file-size=23KB
spring.servlet.multipart.maxRequestSize=23KB

<form action="fileupload" method="post" enctype="multipart/form-data">
    <input type="file" name="filename"/>
    <input type="submit"  />
</form>

@RestController
public class FileUploadController {

    @RequestMapping("/fileupload")
    public Map<String,Object> fileUpload(MultipartFile filename) throws Exception {
        System.out.println(filename.getOriginalFilename());
        System.out.println(filename.getName());
        System.out.println(filename.getSize());
        Map<String,Object> map = new HashMap<>() ;
        filename.transferTo(new File("d:/aaa"));
        map.put("msg","ok");
        return map;
    }