Passing parameter from get to post method - spring

Question

I'm building an feature for a webste where a user can reset his password. He receives an email with a generated token in the url. When this link is clicked, the user is sent to the /reset page. The Get method for that page is the following:
#RequestMapping(value = "/reset", method = RequestMethod.GET)
public ModelAndView displayResetPasswordPage(ModelAndView modelAndView, #ModelAttribute User user, #RequestParam("token") String token) {
User u = userService.findByResetToken(token);
if (u == null) {
modelAndView.setViewName("error/404");
return modelAndView;
} else {
modelAndView.addObject("token", token);
modelAndView.setViewName("resetPassword");
return modelAndView;
}
}
This works fine, if the token in the url is changed, the user is sent to an error page. Now I want to pass this "token" parameter to the post method:
#RequestMapping(value = "/reset", method = RequestMethod.POST)
public ModelAndView setNewPassword(ModelAndView modelAndView, #RequestParam Map<String, String> requestParams, #ModelAttribute User user, BindingResult bindingResult, RedirectAttributes redir) {
System.out.println("token: " + requestParams.get("token"));
User u = userService.findByResetToken(requestParams.get("token"));
// User u = userService.findByEmail(user.getEmail());
if (u != null) {
User updatedUser = userService.updateUserPassword(user);
modelAndView.addObject("User",updatedUser);
modelAndView.setViewName("redirect:login");
return modelAndView;
} else {
modelAndView.setViewName("resetPassword");
}
return modelAndView;
}
This always returns the resetPassword view, since the requestparams.get("token") always returns an empty string. Am I not using the correct method to get the param value?
The reset password view:
<div class="wrapper">
<form class="form-signin" th:action="#{/reset}" method="post" th:object="${user}">
<h2 class="form-signin-heading">Reset wachtwoord</h2>
<input type="hidden" name="token" th:value="*{resetToken}"/>
<div class="form-group">
<input type="password" th:field="*{encryptedPassword}" id="password" class="form-control input-lg"
placeholder="Password" tabindex="3"/>
<div class="form-group">
<input type="password" th:field="*{matchingPassword}" id="password_confirmation"
class="form-control input-lg" placeholder="Confirm Password" tabindex="4"/>
</div>
<div class="row">
<div class="col-xs-6 col-sm-6 col-md-6">
<input type="submit" class="btn btn-secondary" value="Registreer"/>
</div>
</div>
</form>

Answer 1

This can be done by employing the Flash Scope that will allow your token to survive a redirect. You can do that by:
Making the first controller method accessing the second one via a redirect
Using RedirectAttributes on your first controller method and explicitly adding your token into the RedirectAttributes as a Flash Attribute
Take a look at the documentation about RedirectAttributes.