This is my Code, i know that i should not make 2 return statements, but just for explaining my issue. Thanks
#PostMapping
#ResponseStatus(HttpStatus.Created)
public String addStudent(#RequestBody Student student){
return StudentRep.save(Student);// Should be PayLoad Client Response
return “Student”; // Should be redirect to Student.html
}
You don't need to return a ResponseBody. You can simply add attributes to your Model and then use them in your views.
#PostMapping
#ResponseStatus(HttpStatus.Created)
public String addStudent(#RequestBody Student student, Model model){
String id = StudentRep.save(Student);// Should be PayLoad Client Response
model.addAttribute("studentId", id);
// Will redirect to Student.html where you can use the id attribute.
return “Student”;
}
Now, if you were using Thymeleaf, you could use this new attribute anywhere you want in your template. I am not sure how you are creating your templates, so I just used Thymeleaf as an example.
<p th:text=${id}></p>
Now if you want to return a Stundet object, you would need to the following changes to your controller.
#PostMapping
#ResponseStatus(HttpStatus.Created)
public String addStudent(#RequestBody Student student, Model model){
StudentRep.save(Student);// Should be PayLoad Client Response
model.addAttribute("student", student);
// Will redirect to Student.html where you can use the student attribute.
return “Student”;
}
I think that i find the solution of my answer.
I should annotate the controller that contains my method by #RestController instead of #Controller.
So then, the response will automatically return a JSON HTTP response.
Related
I have two controllers. The first send some data using flash parameters to another one
#PostMapping
public String processOrder(Model model, NewOrder order, RedirectAttributes attributes) {
model.addAttribute(order);
attributes.addFlashAttribute("order", order);
return ("redirect:/sendorder");
}
And it's received by:
#GetMapping
public String showSendOrderForm(Model model, #ModelAttribute("order") NewOrder order) {
OrderDetails details = new OrderDetails();
details.setOrder(order);
model.addAttribute("details", details );
model.addAttribute("companies", companyProxy.getCompanies());
return "orderDetails";
}
Can I use value send in Flash attributes in POST method somehow? Or maybe could I use something else instead of Flash attributes?
POST method:
#PostMapping
public String processTaco(Model model, OrderDetails details, SessionStatus sessionStatus) {
detailsProxy.addOrderDetails(details);
sessionStatus.setComplete();
return "redirect:/";
}
Hi I am new to Spring MVC ,I want to call method from one controller to another controller ,how can I do that .please check my code below
#Controller
#RequestMapping(value="/getUser")
#ResponseBody
public User getUser()
{
User u = new User();
//Here my dao method is activated and I wil get some userobject
return u;
}
#Controller
#RequestMapping(value="/updatePSWD")
#ResponseBody
public String updatePswd()
{
here I want to call above controller method and
I want to update that user password here.
how can I do that
return "";
}
any one help me .
Can do like this:
#Autowired
private MyOtherController otherController;
#RequestMapping(value = "/...", method = ...)
#ResponseBody
public String post(#PathVariable String userId, HttpServletRequest request) {
return otherController.post(userId, request);
}
You never have to put business logic into the controller, and less business logic related with database, the transactionals class/methods should be in the service layer. But if you need to redirect to another controller method use redirect
#RequestMapping(value="/updatePSWD")
#ResponseBody
public String updatePswd()
{
return "redirect:/getUser.do";
}
A controller class is a Java class like any other. Although Spring does clever magic for you, using reflection to examine the annotations, your code can call methods just as normal Java code:
public String updatePasswd()
{
User u = getUser();
// manipulate u here
return u;
}
You should place method getUser in a service (example UserService class) .
In the getUser controller, you call method getUser in the Service to get the User
Similarly, in the updatePswd controller, you call method getUser in the Service ,too
Here no need to add #reponseBody annotation as your redirecting to another controller
Your code will look like
#Controller
class ControlloerClass{
#RequestMapping(value="/getUser",method = RequestMethod.GET)
#ResponseBody
public User getUser(){
User u = new User();
//Here my dao method is activated and I wil get some userobject
return u;
}
#RequestMapping(value="/updatePSWD",method = RequestMethod.GET)
public String updatePswd(){
//update your user password
return "redirect:/getUser";
}
}
I have a Spring MVC web application with conroller like below :
#Controller
public class ActionRestController {
#RequestMapping(value = "/list", method = GET)
#ResponseBody
public List<Action> list(Action action, SearhCriteria searchCriteria) {
List<Action> ret = new ArrayList<Action>();
// Call a service method to get the records
// Copy the records into the list
// return the list of objects
return ret;
}
The Controller is invoked when the user does a search. There are several such controllers in the app, one for each searchable entity.
For reasons that I cannot explain very well, here, I cannot modify these controllers in anyway.
But now, I have requirement in the UI to display the search criteria and the no. of records and paging details, as well. This information is not returned by the controller. The JSON returned by the Controller contains just the list of records.
I have put up a different controller which will handle the request, gets and puts the extra info in the model and forwards the request to the existing controller like below :
#Controller
public class ActionExtendedController {
#RequestMapping(value = "/searchlist", method = GET)
#ResponseBody
public List<Action> list(Action action, SearhCriteria searchCriteria, Model model) {
model.addAttribute("searchParameters", searchCriteria);
return "forward:/list";
}
Upto this point, all is well.
What I want to do is intercept the request at a point where the List is returned from the controller, before it is converted to JSON, and return a map containing the list and the search parameters.
Now since the 'immutable' controller users ResponseBody the control goes to the JacksonMessageConverter amd the response goes out from there. I have already tried the following paths and they do not work.
Interceptor - By the time I get here, the response is already written out, so there is no way to change it.
Custom ObjectMapper for the JasksonMessageConverter - Will not work, since I do not have access to the model object inside the mapper, I only have access to the list returned by the controller.
Aspect #After pointcut for the controller - I think this technique will work, but I cannot get it to work. The advise does not fire and I am sure I am missing something in the configuration.
Is there a way to get Spring AOP to fire on a annotated controller, handler method or
can anyone suggest another method of intercepting the handler return value (along with the model) ?
How about a simple delegation to the base controller in your extended controller:
#Controller
public class ActionExtendedController {
#Autowired ActionRestController baseRestController;
#Autowired MappingJacksonJsonView mappingJacksonJsonView;
#RequestMapping(value = "/searchlist", method = GET)
public View list(Action action, SearhCriteria searchCriteria, Model model) {
List<Action> actions = baseRestController.list(action, searchCriteria, model);
model.addAttribute("actions", actions);
model.addAttribute("searchParameters", searchCriteria);
return mappingJacksonJsonView;
}
this way you are delegating to the original controller, but using this new controller for the view. Just register a mappingJacksonJsonView as a bean also which will serialize all model objects (searchcriteria and actions) into the json view. You need not even return a view but can also use #ResponseBody, with a type that can hold the responses and search criteria.
Why don't you change the return type to a Map? Like:
#Controller
public class ActionRestController {
#RequestMapping(value = "/list", method = GET)
#ResponseBody
public Map<String, Object> list(Action action, SearhCriteria searchCriteria) {
Map<String, Object> map = new HashMap<String, Object>();
List<Action> ret = new ArrayList<Action>();
// Call a service method to get the records
// Copy the records into the list
// return the list of objects
map.put("searchResult",ret);
map.put("searchCriteria", searchCriteria);
return map;
}
I am writing a wizard-like controller that handles the management of a single bean across multiple views. I use #SessionAttributes to store the bean, and SessionStatus.setComplete() to terminate the session in the final call. However, if the user abandons the wizard and goes to another part of the application, I need to force Spring to re-create the #ModelAttribute when they return. For example:
#Controller
#SessionAttributes("commandBean")
#RequestMapping(value = "/order")
public class OrderController
{
#RequestMapping("/*", method=RequestMethod.GET)
public String getCustomerForm(#ModelAttribute("commandBean") Order commandBean)
{
return "customerForm";
}
#RequestMapping("/*", method=RequestMethod.GET)
public String saveCustomer(#ModelAttribute("commandBean") Order commandBean, BindingResult result)
{
[ Save the customer data ];
return "redirect:payment";
}
#RequestMapping("/payment", method=RequestMethod.GET)
public String getPaymentForm(#ModelAttribute("commandBean") Order commandBean)
{
return "paymentForm";
}
#RequestMapping("/payment", method=RequestMethod.GET)
public String savePayment(#ModelAttribute("commandBean") Order commandBean, BindingResult result)
{
[ Save the payment data ];
return "redirect:confirmation";
}
#RequestMapping("/confirmation", method=RequestMethod.GET)
public String getConfirmationForm(#ModelAttribute("commandBean") Order commandBean)
{
return "confirmationForm";
}
#RequestMapping("/confirmation", method=RequestMethod.GET)
public String saveOrder(#ModelAttribute("commandBean") Order commandBean, BindingResult result, SessionStatus status)
{
[ Save the payment data ];
status.setComplete();
return "redirect:/order";
}
#ModelAttribute("commandBean")
public Order getOrder()
{
return new Order();
}
}
If a user makes a request to the application that would trigger the "getCustomerForm" method (i.e., http://mysite.com/order), and there's already a "commandBean" session attribute, then "getOrder" is not called. I need to make sure that a new Order object is created in this circumstance. Do I just have to repopulate it manually in getCustomerForm?
Thoughts? Please let me know if I'm not making myself clear.
Yes, sounds like you may have to repopulate it manually in getCustomerForm - if an attribute is part of the #SessionAttributes and present in the session, then like you said #ModelAttribute method is not called on it.
An alternative may be to define a new controller with only getCustomerForm method along with the #ModelAttribute method but without the #SessionAttributes on the type so that you can guarantee that #ModelAttribute method is called, and then continue with the existing #RequestMapped methods in the existing controller.
I've seen examples where a controller returns a String (which indicates the view)
#RequestMapping(value="/owners/{ownerId}", method=RequestMethod.GET)
public String findOwner(#PathVariable String ownerId, Model model) {
Owner owner = ownerService.findOwner(ownerId);
model.addAttribute("owner", owner);
return "displayOwner"
}
And I also see examples where a controller returns a "ModelAndView" object type
public ModelAndView helloWorld() {
ModelAndView mav = new ModelAndView();
mav.setViewName("helloWorld");
mav.addObject("message", "Hello World!");
return mav;
}
What is the difference between the two and which should I use? Cause either way I can get my view resolved.
It's the same logic but it's not the same version of spring.
The ModelAndView object is the spring 2.x way of handling model and views.
In the example you gave, the modelandview object will load the "helloWorld" view (depending on your templating engine could be helloWorld.jsp, or helloWorld.html, ...) with one data "message" in the model.
The other way is the spring 3.x way. You could have wrote exactly the same example as your helloworld.
#RequestMapping(value="/helloWorld", method=RequestMethod.GET)
public String helloWorld(Model model) {
model.addAttribute("message", "Hello World!");
return "helloWorld";
}
The model is automaticly populated at request.
And we can simplify this notation as the url mapping "helloWorld" is directly the view name.
#RequestMapping(value="/helloWorld", method=RequestMethod.GET)
public void helloWorld(Model model) {
model.addAttribute("message", "Hello World!");
}
the helloWorld view will be automaticly loaded
If we are talking about MVC 3, than, both are correct. But directly returning ModelAndView is the old way, and more verbal.
If you are returning just a string (without #ResponseBody which is something else), this string is treated as view name, and spring pushes it to view resolvers - so, you dont have to worry (at least, while you are writing controllers), what type of view renderer you'll use (let it be jsp or velocity, it doesn't matter). You only propagate the Model instance, and returnes a hint what to do with it next. Proper ModelAndView object is made later internally by string.
Generally, spring 3 gives you more flexibility with arguments and return types (see Defining #RequestMapping handler methods section in Spring documentaton).
In Spring MVC, you should return ModelAndView if you want to render jsp page
For example:
#RequestMapping(value="/index.html", method=RequestMethod.GET)
public ModelAndView indexView(){
ModelAndView mv = new ModelAndView("index");
return mv;
}
this function will return index.jsp when you are hitting /index.html
In addition you can return any JSON or XML object using #ResponseBody annotation and serializer.
For example:
#RequestMapping(value="/getStudent.do",method=RequestMethod.POST)
#ResponseBody
public List<Student> getStudent(#RequestParam("studentId") String id){
List<Student> students = daoService.getStudent(id);
return students;
}
In this example you will return List as JSON in case and you have enabled Jackson serializer. In order to enable that you need to add the following to your Spring XML:
<context:annotation-config/>
And the Serializer itself:
<bean id="jacksonMessageConverter" class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter"></bean>
<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
<property name="messageConverters">
<list>
<ref bean="jacksonMessageConverter"/>
</list>
</property>
</bean>
Hope it helps.
Returning ModelAndView or a string does the same job. It resolves into a view (a jsp page) and giving a model object to be rendered in the view. If you return a string, spring internally resolves to a view using viewResolver, create a ModelAndView Object and return it. The returning of ModelAndView object is from the older version. You can do either of this based on your convenient.
Have a look at this question
Also bunch of answers are pointing out to #RequestBody. Its not exactly related to your question. But keep in mind that it will convert your object based on content-type using available converters and the resuly will be part of the document body.
If you are using a template language like freemarker or velocity to create the response then you can return the ModelAndView.
If you want to return a json/xml or some string as the response(ex: ajax requests) then you can use the first method. I think it should be public #ResponseBody String findOwner(#PathVariable String ownerId, Model model), you need to add a annotation called #ResponseBody to indicate that the returned value should be converted as the response text. Using #ResponseBody will enable you to use libraries like Jackson or JaxB to create json/xml responses respectively.
These returned values will be converted using the messageConverters registered with AnnotationMethodHandlerAdapter.
Ref: http://blog.springsource.com/2010/01/25/ajax-simplifications-in-spring-3-0/
public String findOwner(#PathVariable String ownerId, Model model) {
Owner owner = ownerService.findOwner(ownerId);
model.addAttribute("owner", owner);
return "displayOwner"
}
in this method the return type is String and we adding Model as a parameter so to add a value with model we will add like
modelparam.addAttribute("obj",value);
and return to the displayowner to jsp as per view resolver
public ModelAndView helloWorld() {
ModelAndView mav = new ModelAndView();
mav.setViewName("helloWorld");
mav.addObject("message", "Hello World!");
return mav;
}
in this method the return type is ModelAndView so we will return the model
and here the mav is the object of ModelAndView so here we should add like
model.addObject("object","value");
here the viewname is returned to helloworld.jsp as per the viewResolver