Spring MVC - Flash Attribute Examples

@Controller
public class MyController {

    @RequestMapping(value = "test")
    public String handleTestRequest(RedirectAttributes ra) {
        ra.addAttribute("attr", "attrVal");
        ra.addFlashAttribute("flashAttr", "flashAttrVal");
        RedirectView rv = new RedirectView();
        rv.setUrl("/test2");
        return "redirect:/test2";
    }

    @RequestMapping("test2")
    @ResponseBody
    public String handleTest2Request(@RequestParam("attr") String attr,
                                     @ModelAttribute("flashAttr") String flashAttr) {
        return String.format("test2 response attr: %s, flashAttr: %s",
                             attr, flashAttr);
    }
}

@Controller
@RequestMapping
public class UserRegistrationController {

    @Autowired
    private UserService userService;

    @GetMapping(value = "register")
    public String handleGetRequest(Model model) {
        model.addAttribute("user", new User());
        return "user-registration";
    }

    @PostMapping(value = "register")
    public String handlePostRequest(@Valid @ModelAttribute("user") User user,
                                    BindingResult bindingResult,
                                    RedirectAttributes ra) {

        if (bindingResult.hasErrors()) {
            return "user-registration";
        }

        userService.saveUser(user);
        ra.addFlashAttribute("user", user);
        return "redirect:/registration-success";
    }

    @GetMapping(value = "registration-success")
    public String handleRegistrationDone(@ModelAttribute("user") User user) {
        System.out.println("user....: " + user);
        return "registration-done";
    }
}