Performing a redirect from a spring MVC @Exception

问题:

I want to have the following method:

@ExceptionHandler(MyRuntimeException.class)
public String myRuntimeException(MyRuntimeException e, RedirectAttributes redirectAttrs){//does not work
    redirectAttrs.addFlashAttribute("error", e);
    return "redirect:someView";
}

I get a:

java.lang.IllegalStateException: No suitable resolver for argument [1] type=org.springframework.web.servlet.mvc.support.RedirectAttributes]

Is there a way to perform a redirect from an @ExceptionHandler? Or maybe some way to circumvent this restriction?

EDIT:

I have modified my exception handler as follows:

@ExceptionHandler(InvalidTokenException.class)
public ModelAndView invalidTokenException(InvalidTokenException e, HttpServletRequest request) {
RedirectView redirectView = new RedirectView("signin");
return new ModelAndView(redirectView , "message", "invalid token/member not found");//TODO:i18n
}

This is the method that may throw the exception:

@RequestMapping(value = "/activateMember/{token}", method = RequestMethod.GET, produces = "text/html")
public String activateMember(@PathVariable("token") String token) {
    signupService.activateMember(token);
    return "redirect:memberArea/index";
}

The problem with my modified exception handler is that it systematically redirects me to the following URL:

http://localhost:8080/bignibou/activateMember/signin?message=invalid+token%2Fmember+not+found 

Instead of:

http://localhost:8080/bignibou/signin?message=invalid+token%2Fmember+not+found

EDIT 2:

Here is my modified handler method:

@ExceptionHandler(InvalidTokenException.class)
public String invalidTokenException(InvalidTokenException e, HttpSession session) {
session.setAttribute("message", "invalid token/member not found");// TODO:i18n
return "redirect:../signin";
}

The problem I now have is that the message is stuck in the session...

回答1:

Note that this is actually supported out-of-the-box by Spring 4.3.5+ (see SPR-14651 for more details).

I've managed to get it working using the RequestContextUtils class. My code looks like this

@ExceptionHandler(MyException.class)
public RedirectView handleMyException(MyException ex,
                             HttpServletRequest request,
                             HttpServletResponse response) throws IOException {
    String redirect = getRedirectUrl(currentHomepageId);

    RedirectView rw = new RedirectView(redirect);
    rw.setStatusCode(HttpStatus.MOVED_PERMANENTLY); // you might not need this
    FlashMap outputFlashMap = RequestContextUtils.getOutputFlashMap(request);
    if (outputFlashMap != null){
        outputFlashMap.put("myAttribute", true);
    }
    return rw;
}

Then in the jsp page I simply access the attribute

<c:if test="${myAttribute}">
    <script type="text/javascript">
      // other stuff here
    </script>
</c:if>

Hope it helps!

回答2:

You could always forward then redirect (or redirect twice).. First to another request mapping where you have normal access to RedirectAttributes, then again to your final destination.

    @ExceptionHandler(Exception.class)
    public String handleException(final Exception e) {

        return "forward:/n/error";
    }

    @RequestMapping(value = "/n/error", method = RequestMethod.GET)
    public String error(final RedirectAttributes redirectAttributes) {

        redirectAttributes.addAttribute("foo", "baz");
        return "redirect:/final-destination";
    }

回答3:

I am looking at the JavaDoc and I don't see where RedirectAttributes is a valid type that is accepted.

回答4:

Since Spring 4.3.5 (SPR-14651) you can use stright away your first aproach:

@ExceptionHandler(MyRuntimeException.class)
public String myRuntimeException(MyRuntimeException e, RedirectAttributes redirectAttrs){
    redirectAttrs.addFlashAttribute("error", e);
    return "redirect:someView";
}