Spring

Object Storage File Path

@RestController
@RequestMapping("/api/file")
public class FileController {
    @Autowired
    FileService fileService;

    /**
     * File download requests handler
     *
     * @param prefix of relative file path
     *    <ul>
     *        <li>certificates/Policy-8691-191939b9-526b-4933-b05c-61e672609dcc.pdf</li>
     *        <li>certificates/extras/Policy_Wording.pdf</li>
     *    </ul>
     */
    @GetMapping("/{prefix}/**")
    public void fetch(
            @PathVariable("prefix") final String prefix,
            final HttpServletResponse response,
            final HttpServletRequest request
    ) {
        String path = (String) request.getAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE);
        String name = (!ObjectUtils.isEmpty(prefix)) ? path.substring(path.indexOf(prefix)) : null;
        try {
            if (!ObjectUtils.isEmpty(name)) {
                InputStream inputStream = fileService.fetch(name);
                OutputStream outputStream = response.getOutputStream();
                IOUtils.copy(inputStream, outputStream);
            } else throw new FileNotFoundException(name);
        } catch (IOException e) {
            throw new InternalServerException(e.getMessage(), e);
        }
    }
}

ReactJS Route

@Configuration
public class WebConfig implements WebMvcConfigurer {
    public static final String FORWARD_INDEX_HTML = "forward:/index.html";
    public static final String[] PATH_OR_PATTERNS = {
            "/",
            "/{x:[\\w\\-]+}",
            "/{x:^(?!api$).*$}/*/{y:[\\w\\-]+}"
    };
    
    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        Arrays.stream(PATH_OR_PATTERNS).forEach(path -> {
            registry.addViewController(path).setViewName(FORWARD_INDEX_HTML);
        });
    }
}

@Controller
public class HomeController {
    public static final String FORWARD_INDEX_HTML = "forward:/index.html";

    /*
    @RequestMapping(
            value = {
                    "/",
                    "/**",
                    "/{lang:en|my}",
                    "/{lang:en|my}/**",
                    "/{route:^(?!api$).*$}",
                    "/{route:^(?!api$).*$}/**"
            },
            method = {RequestMethod.GET, RequestMethod.POST}
    )
    public ModelAndView index(
            final HttpServletRequest request,
            @PathVariable Optional<String> lang,
            @PathVariable Optional<String> route
    ) throws Exception {
        return new ModelAndView(FORWARD_INDEX_HTML);
    }*/


    @ResponseBody
    @RequestMapping(
            value = {
                    "/",
                    "/**",
                    "/{lang:en|my}",
                    "/{lang:en|my}/**",
                    "/{route:^(?!api$).*$}",
                    "/{route:^(?!api$).*$}/**"
            },
            method = {RequestMethod.GET, RequestMethod.POST}
    )
    public Map<String, String> index(
            final HttpServletRequest request,
            @PathVariable Optional<String> lang,
            @PathVariable Optional<String> route
    ) {
        String path = (String) request.getAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE);
        Map<String, String> response = new HashMap<>();
        response.put("route", route.orElse(""));
        response.put("lang", lang.orElse(""));
        response.put("path", path);
        return response;
    }
}

References

Spring Data Native Queries & Projections in Kotlin Jackson to de-serialize an array of objects Spring Path Variable with Multiple Slash Template Engines for Spring New escape sequences Spring Boot Kotlin Mustache vs Twig
Spring Exception Handling Java Local Date Time Java Interview Java Lambda Locust Java Wrk