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Spring MVC Session check before every request

I am developing a web app using spring boot and mvc. I have controllers and in every controller i have to check if session is exist. In example in getAll method i am checking if session is existing but i have to write this check code in every method , every controller. Is there any shortcut to do that?
#Controller
#RequestMapping("/Sale")
public class SaleController
{
#Autowired
private SaleRepository saleRepository;
#GetMapping
public ModelAndView getAll(#SessionAttribute(required=false) User user)
{
if(user==null)
return new ModelAndView("redirect:/");
else
{
ModelAndView modelAndView=new ModelAndView("/view/sales.jsp");
List<Sale> sales=saleRepository.findAll();
modelAndView.addObject("sales",sales);
return modelAndView;
}
}
}

You can use a Filter and apply it to all requests or only those matching a specific pattern.
To check for a session you would use HttpServletRequest.getSession(false) and check for null.

Spring and Thymeleaf session attributes

I`m creating my first Spring blog and trying to set logged user full name in navbar. Unfortunately sec:authentication="name" gives me user email and ${user.fullname) does not render anything. I figured out to put following code inside in an Article controller
#GetMapping("/")
public String index(Model model) {
List<Article> articles = this.articleRepository.findAll();
Object currentUser = SecurityContextHolder.getContext().getAuthentication().getPrincipal();
if ("anonymousUser".equals(currentUser.toString())) {
model.addAttribute("username","GUEST");
} else {
UserDetails user = (UserDetails) currentUser;
String name = this.userRepository.findByEmail(user.getUsername()).getFullName();
model.addAttribute("username",name);
}
model.addAttribute("view", "home/index");
model.addAttribute("articles", articles);
return "base-layout";
}
And it worked. However i want to use it everywhere and now I can use it only in "/". Please advice how can I modify the code, so I`ll be able to use username in all templates.

You should create a class annotated with #ControllerAdvice which indicates the annotated class assists your Controller. Then create a method  #ModelAttribute which will set the common attributes, shared by all (or most) of your controllers.
For example:
#ControllerAdvice
public class UserControllerAdvice {
#ModelAttribute
public void addUserAttribute() {
Object currentUser = SecurityContextHolder.getContext().getAuthentication().getPrincipal();
if ("anonymousUser".equals(currentUser.toString())) {
model.addAttribute("username","GUEST");
} else {
UserDetails user = (UserDetails) currentUser;
String name = this.userRepository.findByEmail(user.getUsername()).getFullName();
model.addAttribute("username",name);
}
}

Forward request to another controller in Spring MVC

I'd like to know if there is a way I can forward a request from one controller to another without actually changing the URL in the browser.
#RequestMapping(value= {"/myurl"})
public ModelAndView handleMyURL(){
if(somecondition == true)
//forward to another controller but keep the url in the browser as /myurl
}
examples that I found online were redirecting to another url which was causing other controllers to handle that. I don't want to change the URL.

Try to return a String instead of ModelAndView, and the String being the forward url.
#RequestMapping({"/myurl"})
public String handleMyURL(Model model) {
if(somecondition == true)
return "forward:/forwardURL";
}

Instead of forwarding, you may just call the controller method directly after getting a reference to it via autowiring. Controllers are normal spring beans:
#Controller
public class MainController {
#Autowired OtherController otherController;
#RequestMapping("/myurl")
public String handleMyURL(Model model) {
otherController.doStuff();
return ...;
}
}
#Controller
public class OtherController {
#RequestMapping("/doStuff")
public String doStuff(Model model) {
...
}
}

As far as I know "forward" of a request will be done internally by the servlet, so there will not be a second request and hence the URL should remain the same. Try using the following code.
#RequestMapping(value= {"/myurl"})
public ModelAndView handleMyURL(){
if(somecondition == true){
return new ModelAndView("forward:/targetURL");
}
}

Spring MVC session Attribute set intially

I have used the Spring MVC. I set the Session Attribute value like
#RequestMapping(value = "/home", method = RequestMethod.GET)
public String initHome(Model model) {
if (!model.containsAttribute("clientObject")) {
model.addAttribute("clientObject", createDefaultClient());
}
return "homeMenu";
}
It is working fine if i click the home menu url(/home). but if i did not go the
home means it says error as 'session attribute clientObject is required'
so i decided to set sessionattibutes in constructor of controller
#Autowired
public MyController(Model model) {
if (!model.containsAttribute("clientObject")) {
model.addAttribute("clientObject", createDefaultClient());
}
}
it also says error
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'myController'
I tried to set using the RequestMapping also like
#RequestMapping(value = "/", method = RequestMethod.GET)
public void initController(Model model) {
if (!model.containsAttribute("clientObject")) {
model.addAttribute("clientObject", createDefaultClient());
}
}
this method is also not called intially
my cointroller look like
#RequestMapping("/sample")
public class MyController {
..
..
is it possible to set the sessionAttribute value in the constructor of controller? or any other way to set the session Attribute initially?
Thanks in advance for your help.

Assuming your createDefaultClient is in the controller add a #ModelAttribute annotation to it.
#ModelAttribute("clientObject")
public ClientObject createDefaultClient() { ... }
This method will be called before any request handling method (as explained in the reference guide)
If you combine that with a #SessionAttribute annotation on your class (which you might already have). You should be able to achieve what you want.
In your request handling methods (methods annotated with #RequestMapping) you can now simply inject the client object as a method argument.
#RequestMapping(value = "/home", method = RequestMethod.GET)
public String initHome(#ModelAttribute("clientObject") ClientObject clientObject) {
// Do something with the clientObject
return "homeMenu";
}
This will only work consistenly within the same controller, so if you need the ClientObject to be used somewhere else (another controller for instance), this isn't going to work (nor is #SessionAttributes designed for that).

Spring MVC: bind request attribute to controller method parameter

In Spring MVC, it is easy to bind request parameter to method paramaters handling the request. I just use #RequestParameter("name"). But can I do the same with request attribute? Currently, when I want to access request attribute, I have to do following:
MyClass obj = (MyClass) request.getAttribute("attr_name");
But I really would like to use something like this instead:
#RequestAttribute("attr_name") MyClass obj
Unfortunately, it doesn't work this way. Can I somehow extend Spring functionality and add my own "binders"?
EDIT (what I'm trying to achieve): I store currently logged user inside request attribute. So whenever I want to access currently logged user (which is pretty much inside every method), I have to write this extra line user = (User) request.getAttribute("user");. I would like to make it as short as possible, preferably inject it as a method parameter. Or if you know another way how to pass something across interceptors and controllers, I would be happy to hear it.

Well, I finally understood a little bit how models work and what is #ModelAttribute for. Here is my solution.
#Controller
class MyController
{
#ModelAttribute("user")
public User getUser(HttpServletRequest request)
{
return (User) request.getAttribute("user");
}
#RequestMapping(value = "someurl", method = RequestMethod.GET)
public String HandleSomeUrl(#ModelAttribute("user") User user)
{
// ... do some stuff
}
}
The getUser() method marked with #ModelAttribute annotation will automatically populate all User user parameters marked with #ModelAttribute. So when the HandleSomeUrl method is called, the call looks something like MyController.HandleSomeUrl(MyController.getUser(request)). At least this is how I imagine it. Cool thing is that user is also accessible from the JSP view without any further effort.
This solves exactly my problem however I do have further questions. Is there a common place where I can put those #ModelAttribute methods so they were common for all my controllers? Can I somehow add model attribute from the inside of the preHandle() method of an Interceptor?

Use (as of Spring 4.3) #RequestAttribute:
#RequestMapping(value = "someurl", method = RequestMethod.GET)
public String handleSomeUrl(#RequestAttribute User user) {
// ... do some stuff
}
or if the request attribute name does not match the method parameter name:
#RequestMapping(value = "someurl", method = RequestMethod.GET)
public String handleSomeUrl(#RequestAttribute(name="userAttributeName") User user) {
// ... do some stuff
}

I think what you are looking for is:
#ModelAttribute("attr_name") MyClass obj
You can use that in the parameters for a method in your controller.
Here is a link a to question with details on it What is #ModelAttribute in Spring MVC?
That question links to the Spring Documentation with some examples of using it too. You can see that here
Update
I'm not sure how you are setting up your pages, but you can add the user as a Model Attribute a couple different ways. I setup a simple example below here.
#RequestMapping(value = "/account", method = RequestMethod.GET)
public ModelAndView displayAccountPage() {
User user = new User(); //most likely you've done some kind of login step this is just for simplicity
return new ModelAndView("account", "user", user); //return view, model attribute name, model attribute
}
Then when the user submits a request, Spring will bind the user attribute to the User object in the method parameters.
#RequestMapping(value = "/account/delivery", method = RequestMethod.POST)
public ModelAndView updateDeliverySchedule(#ModelAttribute("user") User user) {
user = accountService.updateDeliverySchedule(user); //do something with the user
return new ModelAndView("account", "user", user);
}

Not the most elegant, but works at least...
#Controller
public class YourController {
#RequestMapping("/xyz")
public ModelAndView handle(
#Value("#{request.getAttribute('key')}") SomeClass obj) {
...
return new ModelAndView(...);
}
}
Source : http://blog.crisp.se/tag/requestattribute

From spring 3.2 it can be done even nicer by using Springs ControllerAdvice annotation.
This then would allow you to have an advice which adds the #ModelAttributes in a separate class, which is then applied to all your controllers.
For completeness, it is also possible to actually make the #RequestAttribute("attr-name") as is.
(below modified from this article to suit our demands)
First, we have to define the annotation:
#Retention(RetentionPolicy.RUNTIME)
#Target(ElementType.PARAMETER)
public #interface RequestAttribute {
String value();
}
Then we need a [WebArgumentResolver] to handle what needs to be done when the attribute is being bound
public class RequestAttributeWebArgumentResolver implements WebArgumentResolver {
public Object resolveArgument(MethodParameter methodParameter, NativeWebRequest nativeWebRequest) throws Exception {
// Get the annotation
RequestAttribute requestAttributeAnnotation = methodParameter.getParameterAnnotation(RequestAttribute.class);
if(requestAttributeAnnotation != null) {
HttpServletRequest request = (HttpServletRequest) nativeWebRequest.getNativeRequest();
return request.getAttribute(requestAttributeAnnotation.value);
}
return UNRESOLVED;
}
}
Now all we need is to add this customresolver to the config to resolve it:
<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
<property name="customArgumentResolver">
<bean class="com.sergialmar.customresolver.web.support.CustomWebArgumentResolver"/>
</property>
</bean>
And we're done!

Yes, you can add your own 'binders' to the request attribute - see spring-mvc-3-showcase, or use #Peter Szanto's solution.
Alternatively, bind it as a ModelAttribute, as recommended in other answers.
As it's the logged-in user that you want to pass into your controller, you may want to consider Spring Security. Then you can just have the Principle injected into your method:
#RequestMapping("/xyz")
public String index(Principal principle) {
return "Hello, " + principle.getName() + "!";
}

In Spring WebMVC 4.x, it prefer implements HandlerMethodArgumentResolver
#Override
public boolean supportsParameter(MethodParameter parameter) {
return parameter.getParameterAnnotation(RequestAttribute.class) != null;
}
#Override
public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer,
NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception {
return webRequest.getAttribute(parameter.getParameterAnnotation(RequestAttribute.class).value(), NativeWebRequest.SCOPE_REQUEST);
}
}
Then register it in RequestMappingHandlerAdapter