How To Handle session using Interceptor in Spring 3 - spring

Question

I Want to redirect to login whenever the session goes invalid.My servelt.xml is as follows.
<mvc:interceptors>
<bean class="com.package.login.LoginIntercepter" />
</mvc:interceptors>
Interceptor :
public boolean preHandle(HttpServletRequest request,
HttpServletResponse response, Object handler) throws Exception {
HttpSession session = request.getSession();
HashMap details = (HashMap)session.getAttribute("details");
System.out.println("Pre-handle ::"+request.getRequestURI());
if(details!=null){
/*For Checking the Session
* -----Start-----*/
return true;
}else{
response.sendRedirect("Login");//Here Login is action Name which is Mapped in Login Controller
return false;
}
}
Login Controller :
#RequestMapping(value="/Login", method=RequestMethod.GET)
public String loginMethodWithoutaction(HttpServletRequest request,HttpServletResponse response)
{
String page="login";
HttpSession session = request.getSession();
HashMap details = (HashMap)session.getAttribute("details");
if(details!=null)
page = "redirect:/Home";
return page;
}
If Session is invalid then it has to redirect "login" page. otherwise it has to go Home Controller.But its not working.Whenever application get started, the message get printed multiple times and at the end it gives stack overflow.

Answer 1

Message is printing multiple times because when you redirect request is intercepted again and your session is still null because controller method is not executed yet.
You have to create a method that will set details attribute on successful login in your controller.
#Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
HttpSession session = request.getSession(false);
String path = request.getRequestURI().substring(request.getContextPath().length());
if(path.equals("/Login")){
return true;
}
else if(session == null || session.getAttribute("details") == null) {
request.setAttribute("emassage", "login failed");
throw new LoginFailException("login failed");
}else{
return true;
}
}
LoginFailExceptionClass :
public class LoginFailException extends Exception{
private static final long serialVersionUID = 1L;
public LoginFailException(String message) {
super(message);
}
}
In Controller handle the exception and redirect to login fail page :
#ExceptionHandler(LoginFailException.class)
public String redirectToLogin(){
return "redirect:/login";
}

Answer 2

I think it is your Spring configuration which is not good. Try something like that :
<bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping">
<property name="interceptors">
<ref bean="loginIntercepter"/>
</property>
You have to declare your loginItercepter in the spring file