The question sounds weird, I'm playing around with Spring MVC and am trying to move between two pages and basically I'm creating a JSP page using Spring Form JSTL's so it just uses a POST, and I use a controller to move from one page to the next. But Models are lost from page to page, and I'd like to hide the actual variable so QueryStrings are out of the question(as
far as I know). I know I can use a InternalResourceView, but only allows me to use a model.
I want to transfer a variable that will be exclusive to that page, what's the best way without a model or using QueryStrings?
I was planning on using SessionAttribute to easily define them, but was wondering, how do you remove a SessionAttribute created variable? I tried HttpSession.removeAttribute and it didn't seem to work.
You can also use SessionStatus.setComplete() like this:
#RequestMapping(method = RequestMethod.GET, value="/clear")
public ModelAndView clear(SessionStatus status, ModelMap model, HttpServletRequest request) {
model.clear();
status.setComplete();
return new ModelAndView("somePage");
}
or DefaultSessionAttributeStore.cleanUpAttribute like this:
#RequestMapping(method = RequestMethod.GET, value="/clear")
public ModelAndView clear(DefaultSessionAttributeStore status, WebRequest request, ModelMap model) {
model.remove("mySessionVar");
status.cleanupAttribute(request, "mySessionVar");
return new ModelAndView("somePage");
}
I use it like this on one of my forms that has mulitple sessionAttributes and I want to remove only one of them.
Yes... HttpSession.removeAttribute
You can use the removeAttribute method from the HttpSession class.
you can use WebRequest.removeAttribute(String name, int scope) that works with Spring #SessionAttributes. Quote from #SessionAttributes javadoc - "Alternatively, consider using the attribute management capabilities of the generic {#link org.springframework.web.context.request.WebRequest} interface."
Also look at my example.
#Controller
#SessionAttributes({"sessionAttr"})
public class MyController {
#ModelAttribute("sessionAttr")
public Object defaultSessionAttr() {
return new Object();
}
#RequestMapping(value = "...", method = RequestMethod.GET)
public String removeSessionAttr(WebRequest request, Model model) {
request.removeAttribute("sessionAttr", WebRequest.SCOPE_SESSION);
model.addAttribute("sessionAttr", defaultSessionAttr());
return "myView";
}
}
Related
I have a Spring MVC controller but I'm not sure that it is a good or bad design. As far as I know, api versioning is missing but apart from that I implemented Swagger for documentation and added SpringSecurity and tried to follow YARAS(Yet Another RESTful API Standard) to build it but I need another eye on that to comment it.
#Slf4j
#Controller
#RequestMapping
#RequiredArgsConstructor
public class XGameController implements GameController {
private final GameService gameService;
private final ObjectMapper mapper;
#RequestMapping(value = "/", method= RequestMethod.GET)
public String index() {
return "game";
}
#RequestMapping(value = "/login", method= RequestMethod.GET)
public String login() {
return "login";
}
#Secured("ROLE_USER")
#RequestMapping(value = "/games", method= RequestMethod.POST)
public String initializeGame(Model model) {
log.info("New XGame is initializing...");
Game game = new Game();
game = gameService.initializeGame(game.getId());
try {
model.addAttribute("game", mapper.writeValueAsString(game));
} catch (JsonProcessingException e) {
log.error(e.getMessage());
}
log.info("New XGame is initialized successfully!");
return "game";
}
#Secured("ROLE_USER")
#RequestMapping(value = "/games/{gameId}", method= RequestMethod.PUT)
public #ResponseBody Game play(#PathVariable("gameId") String gameId,
#RequestParam Integer pitNumber,
#RequestParam String action) {
log.info("Sowing stone is triggered...");
return gameService.executeGameRules(UUID.fromString(gameId), pitNumber);
}
#RequestMapping(value = "/403", method= RequestMethod.GET)
public String error403() {
return "/error/403";
}
}
My swagger snapshot;
I would make some changes.
In /games/{gameId} I would use PATCH instead of PUT. The reason is that PUT is intended to completely replace the resource (in your case, the Game). This does not seem to be what you are doing in this endpoint. PATCH is intended to partially update a resource, which seems much more suited to what you are doing here.
Still in /games/{gameId} I would use the request body to provide the needed data instead of query parameters. It simply doesn't seem right. Query parameters are way more suited to GET requests than to POST, PUT or PATCH.
I would rename /403 to something else that actually gives some context about what 403 is. Having said this, I would go with /error-pages/403. Additionally, I would also consider removing this endpoint from the swagger specification.
Other than this, it seems fine to me.
Some advices :
Use a path that represents the context or the idea of your controller and you can add the version
#RequestMapping("/V1/xgame")
Use specialized annotations such as : #GetMapping, #PostMapping etc...
For /403 use a meaning full name such as /errors
Use custom message that you will return to the users. For that you need a ControllerAdvice.
Google on patterns and best practices Rest API design
Read some books for better undertanding.
Firstly, instead of #RequestMapping use a specific Mapping(Get, Post,etc.) and the use of type of mapping is up to you which you find more particular to the cause of using it
if you are redirecting from a page to homepage try to use return "redirect:"/url"" instead of just returning HTML file directly.
Rename your method for error, RequestMapping value to some more reasonable name.
instead of using return "/error/403"
use return "redirect:/error/403"
I have a requirement to implement an HTTP PATCH method in a Spring MVC application. I followed this tutorial: https://www.baeldung.com/http-put-patch-difference-spring.
This is the piece of code:
#RequestMapping(value = "/heavyresource/{id}", method = RequestMethod.PATCH, consumes = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity<?> partialUpdateGeneric(
#RequestBody Map<String, Object> updates,
#PathVariable("id") String id) {
heavyResourceRepository.save(updates, id);
return ResponseEntity.ok("resource updated");
}
The problem is that my repository (JPARepository) does not have a method "save" where I can pass a map and an id.
I tried this implementation on my own:
#PatchMapping("/heavyresource/{id}")
public Beer patchUpdate(#RequestBody HeavyResource heavyResource) {
return heavyResourceRepository.save(heavyResource);
}
But it does not work properly because if I pass only one property (that's the point in PATCH) it let's all the others properties as null and I need to update only the property that was passed. Even thinking in DTOs I was not able to implement.
Thanks!
I have a Spring controller that as return a redirection to another controller.
First looks like this
#RequestMapping(value = "/some-url", method =
{ RequestMethod.POST, RequestMethod.GET })
public String test(final Model model)
{
...
return "redirect:http://someurl/checkout/response";
}
The second is hooking the call of the first controller so it looks like this:
#RequestMapping("/**/response")
public String handleResponse(#RequestParam final MultiValueMap<String, String> params, #Valid #ModelAttribute final Cyber cyber,
final BindingResult bindingResult, final Model model, final HttpSession session, final HttpServletRequest request) throws CMSItemNotFoundException...
I am wondering how to pass the '#RequestedParam params' and the Cyber object from the first controller to the second.
If you additionally want these attributes to be erased automatically from the session after they where consumed, you can alternatively use FlashAttributes. For this you have to declare a RedirectAttributes parameter in method handleResponse and call addFlashAttribute on it. For example addFlashAttribute("cyber", cyber). Those will be available as model attributes in the targeted controller and will be gone out of the session automatically.
You can use #SessionAttributes and send the model to another content.
For more click here
Hi thank you guys I found a solution googleing your suggestion in this link :
http://www.concretepage.com/spring/spring-mvc/spring-mvc-redirectview-example-add-fetch-flash-attributes-redirectattributes-model-requestcontextutils
This is exactly my case.
What is the most elegant/effective way, how to handle Model between Controllers in Spring MVC 3.2. For redirecting to another Controller I use forward method, so there is not necessary new instance of request and Model data should be accessible (if I am not wrong). Is there any way how to catch Model, which was added in first Controller?
(I know about RedirectAttributes, but may be is better/easier method)
Example:
#Controller
public class WebpageController{
#RequestMapping( value = { "/{code}" } )
public String handleFirstLevel(#PathVariable String code, ModelMap modelMap) throws PageNotFoundEception{
final Webpage webpage = getWebpage(code);
modelMap.put(WEBPAGE_MODEL_KEY, prepareModel(webpage));
return "forward:some-url";
}
private Map<String, Object> prepareModel(Webpage webpage){
Map<String, Object> model = new HashMap<String, Object>();
model.put("webpage", webpage);
return model;
}
// some other code
}
#Controller
public class SpecialWebpageController{
#RequestMapping( value = { "/some-url" } )
public String handleFirstLevel(#PathVariable String code, ModelMap modelMap) throws PageNotFoundEception{
// need access to previously appended model to add some other data
return "specialViewName";
}
}
Thank you
When you have a handler method that simply returns a String, that String is considered a view name. With a prefix of forward, Spring will get a RequestDispatcher for the specified path and forward to it. Part of that process will include taking the Model from the ModelAndView created for that request handling cycle and putting all its attributes into the HttpServletRequest attributes.
The Servlet container will take the RequestDispatcher#forward(..) and again use your DispatcherServlet to handle it. Your DispatcherServlet will create a new ModelAndView with a new Model for this handling cycle. Therefore this Model doesn't contain any of the attributes from before but the HttpServletRequest attributes do.
In your case, this
modelMap.put(WEBPAGE_MODEL_KEY, prepareModel(webpage));
will end up being in
HttpServletRequest request = ...;
request.getAttribute(WEBPAGE_MODEL_KEY);
I can't find a solution to this, and it's driving me crazy. I have #Controller mapped that responds to several methods using #RequestMapping. I'd like to tag one of those methods as default when nothing more specific is specified. For example:
#Controller
#RequestMapping("/user/*")
public class UserController {
#RequestMapping("login")
public String login( MapModel model ) {}
#RequestMapping("logout")
public String logout( MapModel model ) {}
#RequestMapping("authenticate")
public String authenticate( MapModel model ) {}
}
So /user/login -> login method, /user/logout -> logout, etc. I'd like to make it so that if someone goes to /user then it routes to one of these methods. However, I don't see anything on #RequestMapping that would allow me to specify one of these methods as a default handler. I also don't see any other annotations that might be used on the class either to do this. I'm beginning to suspect it doesn't exist.
I'm using Spring 2.5.6. Is this solved in 3.0.0? I might just hack Spring to make it work because it's tremendously annoying this isn't more straightforward.
Thanks in Advance.
Take a look at this answer:
Spring MVC and annotated controllers issue
What if you annotate a method with:
#RequestMapping(method = RequestMethod.GET)
You can see an example here:
Spring 3.0 MVC + Hibernate : Simplified with Annotations – Tutorial
The same behavior can be seen here:
Spring Framework 3.0 MVC by Aaron Schram (look at page 21)
Short answer: I do not know how to simply specify one method as default with a simple tag.
But there is this ...
I do not know in which version of Spring this was implemented, but you can provide multiple values to #RequestMapping in 3.1.2. So I do this:
#Controller
#RequestMapping("/user")
public class UserController {
#RequestMapping(value = {"", "/", "/list"}, method = RequestMethod.GET)
public String listUsers(ModelMap model) { }
#RequestMapping(value = "/add", method = RequestMethod.POST)
public ModelAndView add(HttpServletRequest request, ModelMap model) { }
}
The following URLs then map to listUsers():
http://example.com/user
http://example.com/user/
http://example.com/user/list
I would create one default method without RequestMapping's value in there. Please see method defaultCall() below. You can then simply call them with URL: [yourhostname]/user
#Controller
#RequestMapping("/user")
public class UserController {
#RequestMapping(method = RequestMethod.GET)
public String defaultCall( MapModel model ) {
//Call the default method directly, or use the 'forward' String. Example:
return authenticate( model );
}
#RequestMapping("login")
public String login( MapModel model ) {}
#RequestMapping("logout")
public String logout( MapModel model ) {}
#RequestMapping("authenticate")
public String authenticate( MapModel model ) {}
}
Ref: Spring Framework Request Mapping
Simply using #RequestMapping("**") on your default method should work. Any more specific mappings should still pick up their requests. I use this method for setting up default methods sometimes. Currently using Spring v4.3.8.RELEASE.