Spring MVC exception Handling and session additions

setting in Controller

 PackageCom.stone.controller;ImportJava.util.HashMap;ImportJava.util.Map;Importjavax.servlet.http.HttpServletRequest;ImportJavax.validation.Valid;ImportOrg.springframework.stereotype.Controller;ImportOrg.springframework.ui.Model;ImportOrg.springframework.validation.BindingResult;ImportOrg.springframework.web.bind.annotation.ExceptionHandler;Importorg.springframework.web.bind.annotation.PathVariable;Importorg.springframework.web.bind.annotation.RequestMapping;ImportOrg.springframework.web.bind.annotation.RequestMethod;ImportOrg.springframework.web.bind.annotation.ResponseBody;Importorg.springframework.web.bind.annotation.SessionAttributes;ImportOrg.springframework.web.servlet.view.InternalResourceViewResolver;ImportCom.stone.model.User, @Controller @requestmapping ("/USER") @SessionAttributes ("Loginuser")//session to be processed  Public classUsercontroller {Private Final Staticmap<string, user> users =NewHashmap<string, user>();  PublicUsercontroller () {Users.put ("LDH",NewUser ("LDH", "Andy Lau", "123", "[email protected]")); Users.put ("Zxy",NewUser ("Zxy", "Jacky", "123", "[email protected]")); Users.put ("GFC",NewUser ("GFC", "Aaron Kwok", "123", "[email protected]")); Users.put ("LM",NewUser ("LM", "Dawn", "123", "[email protected]")); } @RequestMapping ("/users")     PublicThe String list (model model) {Model.addattribute ("Users", users); return"User/list"; } @RequestMapping (Value= "/login", method =requestmethod.get) PublicString Login () {return"User/login"; } @RequestMapping (Value= "/login", method =requestmethod.post) Publicstring Login (string username, string password, model model) {if(!Users.containskey (username)) {            Throw NewRuntimeException ("User name does not exist! "); }        if(!password.equals (Users.get (username). GetPassword ())) {            Throw NewRuntimeException ("User password is incorrect"); }        //to set the sessionModel.addattribute ("Loginuser", Users.get (username)); return"Redirect:/user/users/"; }        //Perform exception handling@ExceptionHandler (value = {runtimeexception.class })     PublicString handlerexception (Exception ex, HttpServletRequest req) {Req.setattribute ("Ex", ex); return"Error"; }}

Spring MVC exception Handling and session additions