I have a Controller configured on Spring, and I have to workout a DB connection through it to call DAO operations.
This connection is actually available in a session variable, which is not accessible at the momment to the Spring Controller due to it is not HttpServlet inherited.
What is the right way to this Controller access the session variables? Must I implement methods doGet and doPost, inherited from HttpServlet, in order to manipulate the request object? Can it rattle Spring controll over the class?
Thanks for responding.
#Controller
public class SpringController {
#RequestMapping("/create")
public String form(MyCar myCar) {
/*That's where I have to retrieve hibernateSession from
* HttpSession and pass to DAO class do its work.
*/
MyCarDAO myCarDao = new MyCarDAO(session);
myCarDao.saveOrUpdate(myCar);
return "WEB-INF/views/projeto/novo.jsp";
}
}
You can add a HttpSession parameter to your method:
#RequestMapping("/create")
public String form(MyCar myCar, HttpSession session) {
...
}
Spring will automatically add the session parameter when the method is called.
Check the documentation of RequestMapping for possible parameters
Suppose that you declare 3 session attributes, but use only 1 of them in your handler method parameters, so:
#SessionAttributes({ "abc", "def", "ghi" })
public class BindingTestController {
#ModelAttribute("abc")
public String createABC() {
return "abc";
}
#RequestMapping(method = RequestMethod.GET)
public void onGet(#ModelAttribute("abc") String something) {
// do nothing :)
}
#RequestMapping(method = RequestMethod.POST)
public void onPost(#ModelAttribute("abc") String something, BindingResult bindingResult, SessionStatus sessionStatus) {
sessionStatus.setComplete();
}
}
There are lots of example if hit it in google
IMO Right way should be to store the connection in a session-scoped bean instead of a session variable.
Use
#Scope(value = "session")
(cf. http://static.springsource.org/spring/docs/3.0.0.M3/reference/html/ch04s04.html)
Related
I am writing an API using Spring MVC and I am coming up with a problem allowing apps written in different languages to consume my API.
It turns out that the "Ruby users" like to have their params named in snake_case and our "Java users" like to have their param names in camel_case.
Is it possible to create my methods that allow param names to be named multiple ways, but mapped to the same method variable?
For instance... If I have a method that accepts a number of variables, of them there is mapped to a postal code. Could I write my method with a #RequestParam that accepts BOTH "postal_code" and "postalCode" and maps it to the same variable?
Neither JAX-RS #QueryParam nor Spring #RequestParam support your requirement i.e., mapping multiple request parameter names to the same variable.
I recommend not to do this as it will be very hard to support because of the confusion like which parameter is coming from which client.
But if you really wanted to handle this ((because you can't change the URL coming from 3rd parties, agreed long back), then the alternative is to make use of HandlerMethodArgumentResolver which helps in passing our own request argument (like #MyRequestParam) to the controller method like as shown in the below code:
Controller class:
#Controller
public class MyController {
#RequestMapping(value="/xyz")
public void train1(#MyRequestParam String postcode) {//custom method argument injected
//Add your code here
}
}
MyRequestParam :
#Retention(RetentionPolicy.RUNTIME)
#Target(ElementType.PARAMETER)
public #interface MyRequestParam {
}
HandlerMethodArgumentResolver Impl class:
public class MyRequestParamWebArgumentResolver implements HandlerMethodArgumentResolver {
#Override
public Object resolveArgument(MethodParameter parameter,
ModelAndViewContainer mavContainer,
NativeWebRequest webRequest,
WebDataBinderFactory binderFactory) {
MyRequestParam myRequestParam =
parameter.getParameterAnnotation(MyRequestParam.class);
if(myRequestParam != null) {
HttpServletRequest request =
(HttpServletRequest) webRequest.getNativeRequest();
String myParamValueToBeSentToController = "";
//set the value from request.getParameter("postal_code")
//or request.getParameter("postalCode")
return myParamValueToBeSentToController;
}
return null;
}
#Override
public boolean supportsParameter(MethodParameter parameter) {
return (parameter.getParameterAnnotation(MyRequestParam.class) != null);
}
}
WebMvcConfigurerAdapter class:
#Configuration
class WebMvcContext extends WebMvcConfigurerAdapter {
#Override
public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {
argumentResolvers.add(new MyRequestParamWebArgumentResolver());
}
}
I think what you want to do is not allowed by Spring framework with the annotation RequestParam.
But if you can change the code or say to your third party to modify the calls i would suggest you 2 options
Option 1:
Use the #PathVariable property
#RequestMapping(value = "/postalcode/{postalCode}", method = RequestMethod.GET)
public ModelAndView yourMethod(#PathVariable("postalCode") String postalCode) {
//...your code
Here does not matter if the are calling your URL as:
http://domain/app/postalcode/E1-2ES
http://domain/app/postalcode/23580
Option 2:
Create 2 methods in your controller and use the same service
#RequestMapping(value = "/postalcode", method = RequestMethod.GET, params={"postalCode"})
public ModelAndView yourMethod(#RequestParam("postalCode") String postalCode) {
//...call the service
#RequestMapping(value = "/postalcode", method = RequestMethod.GET, params={"postal_code"})
public ModelAndView yourMethodClient2(#RequestParam("postal_code") String postalCode) {
//...call the service
If is possible, I would suggest you option 1 is much more scalable
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";
}
}
In Spring MVC, I can wire session with my method. That's OK.
#RequestMapping(value = "/{cid}/read")
public #ResponseBody
boolean markAsRead(#PathVariable("cid") Comment comment, HttpSession session) {
User user = ((User) session.getAttribute("user"));
... }
Can I wire above user definition to the method definition? I mean instead of wiring session
#RequestMapping(value = "/{cid}/read")
public #ResponseBody
boolean markAsRead(#PathVariable("cid") Comment comment, User user) {
//No need to inject HttpSession and
//no need to call user = ((User) session.getAttribute("user"));
... }
You should be able to retrieve it using the #ModelAttribute tag, and annotating the user as a session attribute, this way:
#SessionAttributes("user")
public class MyController {
#RequestMapping(value = "/{cid}/read")
public #ResponseBody
boolean markAsRead(#PathVariable("cid") Comment comment, #ModelAttribute("user") User user) {
//No need to inject HttpSession and
//no need to call user = ((User) session.getAttribute("user"));
... }
}
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'm using #SessionAttributes on 2 controllers and am experiencing some very strange behavior. My first controller (ViewController) is simply a view controller that displays JSP pages. The other is a controller that handles Ajax requests (AjaxController). I have a session attribute that is simply an object that has a HashMap as a member. The object is a wrapper around the map. The map is populated from the database and put in the session, which displays fine via the ViewController. However, when I do a delete from the map via an ajax request (AjaxController) and refresh the page, ViewController SOMETIMES shows that the element is removed, yet other times the element is still there. Here's code snippets:
ViewController (the homepage simply displays the contents of the map contained by userSettings
#Controller
#SessionAttributes({"userSettings"})
public class ViewController {
#RequestMapping(value="/", method=RequestMethod.GET)
public String home(ModelMap model) {
UserSettings userSettings = (UserSettings) model.get("userSettings");
String userListenersJson = userSettings.toJson(); // for bootsrtapping the js on the front end
return "views/home";
}
}
AjaxController:
#Controller
#SessionAttributes({"userSettings"})
public class AjaxController {
#RequestMapping(value="/users/listeners/{externalId}", method=RequestMethod.DELETE)
public #ResponseBody
AjaxResponse<?> deleteListener(ModelMap model,
#PathVariable long externalId) {
UserSettings userSettings = (UserSettings) model.get("userSettings");
userSettings.removeSetting(externalId);
return new AjaxResponse<String>(null, true);
}
}
Am I using #SessionAttributes wrong here? Why would this work sometimes and not others? I've also tried putting all of the view and ajax functionality in the same controller and experienced the same behavior.
Thanks for any help!
EDIT:
I've refactored my code a bit to use the UserPrincipal via springsecurity. My understanding is that this object is stored in the session. Regardless, I'm seeing exactly the same behavior.
Here's the UserPrincipal constructor that populates the user settings map. I've set breakpoints here to ensure that the correct listenerDBOs are set - they are, every time. This is the only time the listeners get set from the db into the UserSettings object in CustomUserPrincipal. All other adds/removes are done via the controllers (quick aside: adds never fail... only removes):
public CustomUserPrincipal(UserDBO userDBO) {
// set UserSettings obj
UserSettingsAdapter.addListeners(userDBO.getUserListenerDBOs(), userSettings);
}
The UserSettings object itself:
public class UserSettings implements Serializable {
private static final long serialVersionUID = -1882864351438544088L;
private static final Logger log = Logger.getLogger(UserSettings.class);
private Map<Long, Listener> userListeners = Collections.synchronizedMap(new HashMap<Long, Listener>(1));
// get the listeners as an arraylist
public List<Listener> userListeners() {
return new ArrayList<Listener>(userListeners.values());
}
public Map<Long, Listener> getUserListeners() {
return userListeners;
}
public Listener addListener(Listener listener) {
userListeners.put(listener.getId(), listener);
return listener;
}
// I'm logging here to try and debug the issue. I do see the success
// message each time this function is called
public Listener removeListener(Long id) {
Listener l = userListeners.remove(id);
if (l == null) {
log.info("failed to remove listener with id " + id);
} else {
log.info("successfully removed listener with id " + id);
}
log.info("Resulting map: " + userListeners.toString());
log.info("Map hashcode: " + userListeners.hashCode());
return l;
}
public Listener getListener(long id) {
return userListeners.get(id);
}
}
This is the helper function in the UserSettingsAdapter class that adds to the UserSettings object, called from CustomUserDetails constructor:
public static void addListeners(Set<UserListenerDBO> userListeners, UserSettings userSettings) {
for (UserListenerDBO userListenerDBO : userListeners) {
if (userListenerDBO.isActive()) {
addListener(userListenerDBO, userSettings);
}
}
}
I've also changed the controller code to user the CustomUserPrincipal object instead of #SessionAttributes:
In ViewController:
#RequestMapping(value="/", method=RequestMethod.GET)
public String home(ModelMap model) {
CustomUserPrincipal userPrincipal = authenticationHelpers.getUserPrincipal();
UserSettings userSettings = userPrincipal.getUserSettings();
String userListenersJson = userSettings.toJson();
return "views/home";
}
In AjaxController:
#RequestMapping(value="/users/listeners/{externalId}", method=RequestMethod.DELETE)
public #ResponseBody
AjaxResponse<?> deleteListener(ModelMap model,
#PathVariable long externalId) {
CustomUserPrincipal userPrincipal = authenticationHelpers.getUserPrincipal();
UserSettings userSettings = userPrincipal.getUserSettings();
userSettings.removeListener(externalId);
return new AjaxResponse<String>(null, true);
}
I hope this helps shed some light on the issue!
I ran into a similar problem with #SessionAttributes. A controller had a #SessionAttributes annotation at the class level, and one of the methods handled POST requests, and included an instance of the session-managed object as an argument. This instance was saved to the database, but was re-used by subsequent requests, causing some data corruption. We had to add another method argument of type SessionStatus, and call SessionStatus.setComplete(). This caused the instance to be removed from the session, and prevented reuse and corruption. So try adding a SessionStatus instance to your controllers' handler methods, and invoke setComplete() where appropriate.
EDIT: I accidentally referenced the getter isComplete() in my initial answer; I meant to reference the setter setComplete().
#SessionAttributes is specific to a Controller and is not shared among several Controllers.
Instead, consider using manually session.setAttribute (class HttpSession).
You should have a look here : http://beholdtheapocalypse.blogspot.fr/2013/01/spring-mvc-framework-sessionattributes.html