I have the following method skeleton in a Spring MVC application:
#RequestMapping(value = "/activateMember/{token}", method = RequestMethod.GET, produces = "text/html")
public String activateMember(#PathVariable("token") String token) {
...
}
I am trying to display an error message if the token is invalid for some reason. However I have no ModelAttribute in the method arguments and I don't really want one. But of course I can't use an Errors or BindingResults argument because of the absence of a ModelAttribute and its corresponding form.
So my question is:
what is the recommended way to display an error message given the above method signature and without introducing a ModelAttribute?
If the String you've returned from the method is a viewname (Spring default) then simply create a view for this case and do like:
#RequestMapping()
public String activateMember(#PathVariable("token") String token) {
if(checkToken(token)){
doProcess();
return "userprofile";
} else {
return "badtoken"
}
}
In more complicated case you may have a hierarchy of exceptions, related to bad tokens. (Token is expired, token is just incorrect and so on). You can register an #ExceptionHandler in the same controller:
#RequestMapping()
public String activateMember(#PathVariable("token") String token) {
return activate(token); // This method may throw TokenException and subclasses.
}
#ExceptionHandler(TokenException.class)
public ModelAndView tokenException(TokenException e){
// some code
return new ModelAndView("badtoken", "exception", e);
}
Related
I am very new to spring boot and I can't figure out the #Controller class. What should I pass if I can't find a particular object in my DB in spring boot? Is it better if I declare my return type as Response Entity and send a null User object?
//Get single user
#GetMapping("/users/{id}")
public User getUser(#PathVariable String id){
try {
Long i = Long.parseLong(id);
} catch (NumberFormatException ex) {
return ???? //Can't figure out what to return here.
}
return userService.getUser(id);
}
I want the consumer to know that they've sent an invalid string.
2) Also, User's variable id is of Long type. So should I take the argument as Long in the getUser function or take a String and parse it? Taking a Long would crash my server if a string was sent in the link.
This is my typical code of a REST controller for 'get user by id' request:
#RestController
#RequestMapping("/users") // 1
public class UserController {
private final UserRepo userRepo;
public UserController(UserRepo userRepo) {
this.userRepo = userRepo;
}
#GetMapping("/{id}") // 2
public ResponseEntity getById(#PathVariable("id") Long id) { // 3
return userRepo.findById(id) // 4
.map(UserResource::new) // 5
.map(ResponseEntity::ok) // 6
.orElse(ResponseEntity.notFound().build()); // 7
}
}
Where:
1 - is a common starting path for all requests handled by this controller
2 - a path variable pattern of GET request (/users/{id}).
3 - provide the name of path variable which name is correspond to the parameter in GetMapping. The type of the parameter in getById method is corresponds to the type of User ID.
4 - I use findById method of my UserRepo that return Optional
5 - Here I transform User to some type of DTO - UserResource (it's optional step)
6 - return OK response if User was found
7 - or return Not Found response otherwise.
I'm also using the controller-service-repository pattern in a couple of projects, and this is how I lay it out:
Controller.java
#RestController // 1
#RequestMapping(value = "/users") // 2
public class UserController {
private final UserService userService;
#Autowired // 3
public UserController(UserService userService) {
this.userService = userService;
}
#RequestMapping(value = "/{user_id}", method = RequestMethod.GET) //4
#ResponseStatus(HttpStatus.OK) //5
public UserModel getUser(#PathVariable(value="user_id") long user_id) { //6
return userService.getUserById(user_id);
}
#RequestMapping(method = RequestMethod.POST) // 7
#ResponseStatus(HttpStatus.CREATED) // 8
public UserModel getUser(#ResponseBody UserModel userModel) { // 9
return userService.createUser(usermodel);
}
}
1) #RestController is a combination of #Controller and #ResponseBody, which essentially means every method in your class will have a response body.
2) Prefix #RequestMapping values in this class with /users
3) Autowiring in the Constructor is the safest approach to injecting beans.
4) This method will be accessible via a GET request to /users/{user_id}
5) This method will return HttpStatus.OK status code on success (200)
6) Extracts the path variable "user_id" from the Request. Use the same numeric type as your user id's here (i.e. int or long).
7) This method will be accessible via a POST request to /users
8) This method will return HttpStatus.CREATED status code on success (201)
9) Extracts a UserModel from the request body (should have the same structure as the json given later).
There are no real differences to Cepr0 and my approach, it's purely a style preference.
UserModel can be a class like this:
UserModel.java
public class UserModel {
private String username;
// Constructor, Getter, Setter...
}
And this will return a JSON object in the body of the response like this:
{
"username":"username"
}
If you would like to handle Exceptions within your controller (and even control the data returned by an exception, you can use #ExceptionHandler like so:
#ExceptionHandler(Exception.class)
public ResponseEntity<ErrorResponseWrapper> handleGenericException(Exception ex){
return ResponseEntity
.status(HttpStatus.I_AM_A_TEAPOT)
.body(new CustomExceptionWrapper(ex)));
}
Where CustomExceptionHandler converts exceptions thrown by your application into a format you decide (This can also be a POJO and Spring Boot will transform it into JSON for you!)
To answer your questions more specifically:
1) You should throw an exception if the user isn't found that will include the response status 404 (NOT FOUND). Returning null is typically a bad idea as it could mean a lot of things.
1.1?) If your user sends an invalid string, you can look up which exception it causes in your server, and use the exception handler to deal with it and return an appropriate response (BAD_REQUEST maybe?)
2) Yes use long if your use id's are longs.
Check out the baeldung site, would really recommend them for learning Spring Boot.
We are using spring and spring-security-3.2. Recently We are adding annotations #PreAuthorize to RestAPIs(earlier it was URL based).
#PreAuthorize("hasPermission('salesorder','ViewSalesOrder')")
#RequestMapping(value = "/restapi/salesorders/", method = RequestMethod.GET)
public ModelAndView getSalesOrders(){}
We already have Global exception handler which annotated with - #ControllerAdvice and custom PermissionEvaluator in place, everything works fine except the error message.
Lets say some user is accessing API At moment without having 'ViewSalesOrder' permission then spring by default throws the exception 'Access is denied',but didn't tell which permission is missing (Its our requirement to mention which permission is missing).
Is it possible to throw an exception which also include the permission name, so final error message should be look like "Access is denied, you need ViewSalesOrder permission"(here permission name should be from #PreAuthorize annotation)?
Please note that we have 100 such restAPI in place so generic solution will be highly appreciated.
There is no pretty way of achieving what you expect since PermissionEvaluator interface doesn't let you pass the missing permission along with the result of the evaluation.
In addition, AccessDecisionManager decides on the final authorization with respect to the votes of the AccessDecisionVoter instances, one of which is PreInvocationAuthorizationAdviceVoter which votes with respect to the evaluation of #PreAuthorize value.
Long story short, PreInvocationAuthorizationAdviceVoter votes against the request (giving the request –1 point) when your custom PermissionEvaluator returns false to hasPermission call. As you see there is no way to propagate the cause of the failure in this flow.
On the other hand, you may try some workarounds to achieve what you want. One way can be to throw an exception within your custom PermissionEvaluator when permission check fails. You can use this exception to propagate the missing permission to your global exception handler. There, you can pass the missing permission to your message descriptors as a parameter. Beware that this will halt execution process of AccessDecisionManager which means successive voters will not be executed (defaults are RoleVoter and AuthenticatedVoter). You should be careful if you choose to go down this path.
Another safer but clumsier way can be to implement a custom AccessDeniedHandler and customize the error message before responding with 403. AccessDeniedHandler provides you current HttpServletRequest which can be used to retrieve the request URI. However, bad news in this case is, you need a URI to permission mapping in order to locate the missing permission.
I have implemented the second possible solution mentioned by Mert Z. My solution works only for #PreAuthorize annotations used in the API layer (e.g. with #RequestMapping). I have registered a custom AccessDeniedHandler bean in which I get the value of the #PreAuthorize annotation of the forbidden API method and fills it into error message.
public class CustomAccessDeniedHandler implements AccessDeniedHandler {
private DispatcherServlet dispatcherServlet;
public void handle(HttpServletRequest request, HttpServletResponse response,
AccessDeniedException accessDeniedException) throws IOException,
ServletException {
if (!response.isCommitted()) {
List<HandlerMapping> handlerMappings = dispatcherServlet.getHandlerMappings();
if (handlerMappings != null) {
HandlerExecutionChain handler = null;
for (HandlerMapping handlerMapping : handlerMappings) {
try {
handler = handlerMapping.getHandler(request);
} catch (Exception e) {}
if (handler != null)
break;
}
if (handler != null && handler.getHandler() instanceof HandlerMethod) {
HandlerMethod method = (HandlerMethod) handler.getHandler();
PreAuthorize methodAnnotation = method.getMethodAnnotation(PreAuthorize.class);
if (methodAnnotation != null) {
response.sendError(HttpStatus.FORBIDDEN.value(),
"Authorization condition not met: " + methodAnnotation.value());
return;
}
}
}
response.sendError(HttpStatus.FORBIDDEN.value(),
HttpStatus.FORBIDDEN.getReasonPhrase());
}
}
#Inject
public void setDispatcherServlet(DispatcherServlet dispatcherServlet) {
this.dispatcherServlet = dispatcherServlet;
}
}
The handler is registered in WebSecurityConfigurerAdapter:
#EnableGlobalMethodSecurity(jsr250Enabled = true, prePostEnabled = true)
#EnableWebSecurity
public abstract class BaseSecurityInitializer extends WebSecurityConfigurerAdapter {
#Override
protected void configure(HttpSecurity http) throws Exception {
...
http.exceptionHandling().accessDeniedHandler(accessDeniedHandler());
...
}
#Bean
public AccessDeniedHandler accessDeniedHandler() {
return new CustomAccessDeniedHandler();
}
}
Beware that if there is also a global resource exception handler with #ControllerAdvice the CustomAccessDeniedHandler won't be executed. I solved this by rethrowing the exception in the global handler (as advised here https://github.com/spring-projects/spring-security/issues/6908):
#ControllerAdvice
public class ResourceExceptionHandler {
#ExceptionHandler(AccessDeniedException.class)
public ResponseEntity accessDeniedException(AccessDeniedException e) throws AccessDeniedException {
log.info(e.toString());
throw e;
}
}
You can throw an org.springframework.security.access.AccessDeniedException from a method that was called inside an EL-Expression:
#PreAuthorize("#myBean.myMethod(#myRequestParameter)")
Ideally, the #PreAuthorize annotation should be supporting String message(); in addition to the SpEl value. But, for whatever reason, it does not. Most of the suggestions here seem unnecessarily cumbersome and elaborate. As #lathspell has suggested, the simplest way to provide your own error message - along with any custom access validation logic - would be to add a simple method that performs the check and throws the AccessDeniedException in case the check fails, and then reference that method in the SpEl expression. Here's an example:
#RestController
#RequiredArgsConstructor // if you use lombok
public class OrderController {
private final OrderService orderService;
...
#GetMapping(value = "/salesorders", produces = MediaType.APPLICATION_JSON_VALUE)
#PreAuthorize("#orderController.hasPermissionToSeeOrders(#someArgOfThisMethod)")
public Page<OrderDto> getSalesOrders(
// someArgOfThisMethod here, perhaps HttpRequest, #PathVariable, #RequestParam, etc.
int pageIndex, int pageSize, String sortBy, String sortOrder) {
Pageable pageRequest = PageRequest.of(pageIndex, pageSize, Sort.Direction.fromString(sortOrder), sortBy);
return ordersService.retrieveSalesOrders(..., pageRequest);
}
public static Boolean hasPermissionToSeeOrders(SomeArgOfTheTargetMethod argToEvaluate) {
//check eligibility to perform the operation based on some data from the incoming objects (argToEvaluate)
if (condition fails) {
throw new AccessDeniedException("Your message");
}
return true;
}
I have this Object
public class Deportista implements Serializable {
private static final long serialVersionUID = 6229604242306465153L;
private String id;
...
#NotNull(message="{field.null}")
public String getId() {
return id;
}
...
}
I have the following Controller's methods
#InitBinder(value="deportistaRegistrar")
public void registrarInitBinder(WebDataBinder binder) {
logger.info(">>>>>>>> registrarInitBinder >>>>>>>>>>>>>");
}
#RequestMapping(value="/registrar.htm", method=RequestMethod.GET)
public String crearRegistrarFormulario(Model model){
logger.info("crearRegistrarFormulario GET");
Deportista deportista = new Deportista();
model.addAttribute("deportistaRegistrar", deportista);
return "deportista.formulario.registro";
}
#RequestMapping(value="/registrar.htm", method=RequestMethod.POST)
public String registrarPerson(#Validated #ModelAttribute("deportistaRegistrar") Deportista deportista,
BindingResult result){
logger.info("registrarPerson POST");
logger.info("{}", deportista.toString());
if(result.hasErrors()){
logger.error("There are errors!!!!");
for(ObjectError objectError : result.getAllErrors()){
logger.error("Error {}", objectError);
}
return "deportista.formulario.registro";
}
logger.info("All fine!!!!");
this.fakeMultipleRepository.insertDeportista(deportista);
return "redirect:/manolo.htm";
}
Until here the Controller is able to create a form (GET) and submit (POST) a new command object, Validation code works well.
The problem is with the update.
I have the following:
#InitBinder(value="deportistaActualizar")
public void actualizarInitBinder(WebDataBinder binder) {
logger.info(">>>>>>>> actualizarInitBinder >>>>>>>>>>>>>");
binder.setDisallowedFields("id");
}
Observe I have binder.setDisallowedFields("id")
public String crearActualizarFormulario(#PathVariable("id") String id, Model model){
logger.info("crearActualizarFormulario GET");
Deportista deportista = this.fakeMultipleRepository.findDeportista(id);
model.addAttribute("deportistaActualizar", deportista);
return "deportista.formulario.actualizacion";
}
#RequestMapping(value="/{id}/actualizar.htm", method=RequestMethod.POST)
public String actualizarPerson(#Validated #ModelAttribute("deportistaActualizar") Deportista deportista,
BindingResult result){
logger.info("actualizarPerson POST");
logger.info("{}", deportista.toString());
if(result.hasErrors()){
logger.error("There are errors!!!!");
for(ObjectError objectError : result.getAllErrors()){
logger.error("Error {}", objectError);
}
return "deportista.formulario.actualizacion";
}
logger.info("All fine!!!!");
this.fakeMultipleRepository.updateDeportista(deportista);
return "redirect:/manolo.htm";
}
The problem is:
when the form or command has any error, the controller re-render the view and the form appear showing the error messages how is expected, but without the ID value
or
if I try to update the object, of course keeping the id value, and without any error to simply proceed to update, it fails
The following appears in the Console:
- -------- createCollections ---------------
- >>>>>>>> actualizarInitBinder >>>>>>>>>>>>>
- Skipping URI variable 'id' since the request contains a bind value with the same name.
- actualizarPerson POST
- Deportista [id=null, nombre=Manuel, ...]
- There are errors!!!!
- Error Field error in object 'deportistaActualizar' on field 'id': rejected value [null]; codes [NotNull.deportistaActualizar.id,NotNull.id,NotNull.java.lang.String,NotNull]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [deportistaActualizar.id,id]; arguments []; default message [id]]; default message [The field must be not empty]
The id is null. How I can around this problem keeping the Request Scope?
I have an alternate controller which is working with #SessionAttributes and all works perfect. But since is a huge risk if the user has many tabs open in the same web browser, one for create and other for updating, all is going to be very wrong. According with Spring MVC + Session attributes and multiple tabs, request scope should be used instead of session scope. It has sense.
Sadly seems Spring is not going to fix this:
#SessionAttributes doesn't work with tabbed browsing
Addition
According with your suggestion, I have the following:
#ModelAttribute("deportistaActualizar")
public Deportista populateActualizarFormulario(#RequestParam(defaultValue="") String id){
logger.info("populateActualizarFormulario - id: {}", id);
if(id.equals(""))
return null;
else
return this.fakeMultipleRepository.findDeportista(id);
}
Observe the method uses #RequestParam, my problem is how update that method to work when the URL to update has the following style
http://localhost:8080/spring-utility/deportista/1/actualizar.htm. There is no param in the URL, therefore #RequestParam is useless now.
I already have read the Spring Reference documentation:
Using #ModelAttribute on a method
Second Addition
Yes, you was right, and I did that yesterday, but I forget to share the following:
#ModelAttribute("deportistaActualizar")
public Deportista populateActualizarFormulario(#PathVariable(value="id") String id){
logger.info("populateActualizarFormulario - id: {}", id);
if(id.equals(""))
return null;
else
return this.fakeMultipleRepository.findDeportista(id);
}
Since a #ModelAttribute is called always before by any handler method, the following URL fails http://localhost:8080/spring-utility/deportista/registrar.htm, the following appears on the page
HTTP Status 400 -
type Status report
message
description The request sent by the client was syntactically incorrect.
Of course because the URL does not contains the expected id. Therefore I can't create new records to later edit/see.
I can confirm, that for the following work:
http://localhost:8080/spring-utility/deportista/1/detalle.htm
http://localhost:8080/spring-utility/deportista/1/actualizar.htm
the id (1) is retrieved.
How I could resolve this?
Thank You
I am really not sure if this is feasible using Spring 3.2 MVC.
My Controller has a method declared as below:
#RequestMapping(method = RequestMethod.GET)
#ResponseStatus(HttpStatus.OK)
public #ResponseBody List<Foo> getAll(){
return service.getAll();
}
Questions:
What is the meaning of #ResponseStatus(HttpStatus.OK) ?
Does it signifies that the method will always return a HttpStatus.OK status code.
What if an exception is thrown from the service layer?
Can I change the Response Status on occurrence of any exception?
How can I handle multiple response statuses depending on conditions in the same method?
#ResponseStatus(HttpStatus.OK) means that the request will return OK if the handling method returns normally (this annotation is redundant for this case, as the default response status is HttpStatus.OK). If the method throws an exception, the annotation does not apply; instead, the status will be determined by Spring using an exception handler.
How can I handle multiple response statuses depending on conditions in the same method?
That question has already been asked.
Can I change the Response Status on occurrence of any exception
You have two choices. If the exception class is one of your own, you could annotate the exception class with #ResponseStatus. The other choice is to provide the controller class with an exception handler, annotated with #ExceptionHandler, and have the exception handler set the response status.
If you return a ResponseEntity directly, you can set the HttpStatus in that:
// return with no body or headers
return new ResponseEntity<String>(HttpStatus.NOT_FOUND);
If you want to return an error other than 404, HttpStatus has lots of other values to choose from.
You cannot set multiple status value for #ResponseStatus. One approach I can think of is to use #ExceptionHandler for response status which is not HttpStatus.OK
#RequestMapping(value = "login.htm", method = RequestMethod.POST)
#ResponseStatus(HttpStatus.OK)
public ModelAndView login(#ModelAttribute Login login) {
if(loginIsValidCondition) {
//process login
//.....
return new ModelAndView(...);
}
else{
throw new InvalidLoginException();
}
}
#ExceptionHandler(InvalidLoginException.class)
#ResponseStatus(HttpStatus.BAD_REQUEST)
public ModelAndView invalidLogin() {
//handle invalid login
//.....
return new ModelAndView(...);
}
Situation
I'm trying to group the code that logs the exceptions and render a nice view in a few methods. At the moment the logic is sometime in the #RequestHandler itself (in the a catch block), othertimes is delegated to an utility class (that works but moves the logic away from the place where the exception is thrown).
Spring's #ExceptionHandler seemed the way to group everything in one place (the controller itself or a parent) and get rid of some code (no need to put logic in the try-catch and no need for an utility class)... until I realized that an #ExceptionHandler methods won't have the ModelMap or BindingResult parameters autowired. Currently those objects are used to render the view with a sensible error message and we want to log some information contained in these objects as well.
Question
Why Spring doesn't not support method arguments such ModelMap or BindingResult for the #ExceptionHandler? What is the rationale behind it?
Possible solution
In the Spring source code (3.0.5) the arguments for the method are resolved in the HandlerMethodInvoker.invokeHandlerMethod. A an exception thrown by the request handler is caught there and re-thrown. The #ExceptionHandler and it's parameters are resolved elsewhere. As a workaround I thought to check if the Exception implements an hypothetical "ModelAware" or "BindingResultAware" interface, and in that case set Model and BindingResult attributes before re-throwhing it.
How does it sound?
As stated before you can raise an exception wrapping a binding result object in some method of your controller:
if (bindingResult.hasErrors()) {
logBindingErrors(bindingResult);
//return "users/create";
// Exception handling happens later in this controller
throw new BindingErrorsException("MVC binding errors", userForm, bindingResult);
}
With your exception defined as illustrated here:
public class BindingErrorsException extends RuntimeException {
private static final Logger log = LoggerFactory.getLogger(BindingErrorsException.class);
private static final long serialVersionUID = -7882202987868263849L;
private final UserForm userForm;
private final BindingResult bindingResult;
public BindingErrorsException(
final String message,
final UserForm userForm,
final BindingResult bindingResult
) {
super(message);
this.userForm = userForm;
this.bindingResult = bindingResult;
log.error(getLocalizedMessage());
}
public UserForm getUserForm() {
return userForm;
}
public BindingResult getBindingResult() {
return bindingResult;
}
}
Next you just have to extract the required information from the raised then caught exception. Here assuming you have a suitable exception handler defined on your controller. It might be in a controller advice instead or even elewhere. See the Spring documentation for suitable and appropriate locations.
#ExceptionHandler(BindingErrorsException.class)
public ModelAndView bindingErrors(
final HttpServletResponse resp,
final Exception ex
) {
if(ex instanceof BindingErrorsException) {
final BindingErrorsException bex = (BindingErrorsException) ex;
final ModelAndView mav = new ModelAndView("users/create", bex.getBindingResult().getModel());
mav.addObject("user", bex.getUserForm());
return mav;
} else {
final ModelAndView mav = new ModelAndView("users/create");
return mav;
}
}
I ran into to same problem a while ago. The ModelMap or BindingResult are explicitly not listed as supported argument types in the JavaDocs of #ExceptionHandler, so this must have been intentional.
I reckon the reason behind it being that throwing exceptions in general could leave your ModelMap in an inconsistent state. So depending on your situation you might consider
Explicitly catch the exception to tell Spring MVC that you know what you're doing (you could use the Template pattern to refactor exception handling logic into one single place)
If you're in control of the exception hierarchy you could hand over the BindingResult to the exception and extract it from the exception later for rendering purposes
Not throw an exception in the first place, but use some result code (just like BeanValidation does for example)
HTH
To improve the first answer:
#ExceptionHandler(value = {MethodArgumentNotValidException.class})
#ResponseStatus(HttpStatus.BAD_REQUEST)
#ResponseBody
public VndErrors methodArgumentNotValidException(MethodArgumentNotValidException ex, WebRequest request) {
List<FieldError> fieldErrors = ex.getBindingResult().getFieldErrors();
List<ObjectError> globalErrors = ex.getBindingResult().getGlobalErrors();
List<VndError> errors = new ArrayList<>(fieldErrors.size() + globalErrors.size());
VndError error;
for (FieldError fieldError : fieldErrors) {
error = new VndError(ErrorType.FORM_VALIDATION_ERROR.toString(), fieldError.getField() + ", "
+ fieldError.getDefaultMessage());
errors.add(error);
}
for (ObjectError objectError : globalErrors) {
error = new VndError(ErrorType.FORM_VALIDATION_ERROR.toString(), objectError.getDefaultMessage());
errors.add(error);
}
return new VndErrors(errors);
}
There is already MethodArgumentNotValidException has already a BindingResult object, and you can use it, if you don't need to create an specific exception for this purpose.
I had the same problem to "add" FunctinalException to ourthe BindingResult
To resolve it, we use aop, if the controller method throws a runtime exception (or the one you want),
the aop catch it and update the bindingresult or model (if they are args of the method).
The method has to be annoted with a specific annotation containing the error path (configurable for specific exception if necessary).
It is not the best way because developer must not forget to add args that he don't use in its method but Spring does not provide a simple system to do this need.
I've wondered this too.
In order to handle bean validation in a way that allows for a non-global error view to display any ConstraintViolationExceptions that may be thrown, I opted for a solution along the lines of what #Stefan Haberl proposed:
Explicitly catch the exception to tell Spring MVC that you know what you're doing (you could use the Template pattern to refactor exception handling logic into one single place)
I created a simple Action interface:
public interface Action {
String run();
}
And an ActionRunner class which does the work of ensuring ConstraintViolationExceptions are handled nicely (basically the messages from each ConstraintViolationException is simply added to a Set and added to the model):
public class ActionRunner {
public String handleExceptions(Model model, String input, Action action) {
try {
return action.run();
}
catch (RuntimeException rEx) {
Set<String> errors = BeanValidationUtils.getErrorMessagesIfPresent(rEx);
if (!errors.isEmpty()) {
model.addAttribute("errors", errors);
return input;
}
throw rEx;
}
}
}
Java 8 makes this pretty nice to run within the controller action method:
#RequestMapping(value = "/event/save", method = RequestMethod.POST)
public String saveEvent(Event event, Model model, RedirectAttributes redirectAttributes) {
return new ActionRunner().handleExceptions(model, "event/form", () -> {
eventRepository.save(event);
redirectAttributes.addFlashAttribute("messages", "Event saved.");
return "redirect:/events";
});
}
This is to wrap up those action methods for which I'd like to explicitly handle exceptions that could be thrown due to Bean Validation. I still have a global #ExceptionHandler but this deals with only "oh crap" exceptions.
Actually it does, just create an #ExceptionHandler method for MethodArgumentNotValidException.
That class gives you access to a BindingResult object.