How to do something on session start in Spring MVC?

Question

Hello everyone.

I need to initialize every new http session with some values. How do I do that?

I tried to create a session-scoped component and initializing session in @PostConstruct, but session-scoped beans are not eagerly created until I request access them.

Answer 1

If you are absolutely certain that your want eager initialization, you can do the following:

• define an interceptor for all beans

• defina a <lookup-method> for that interceptor:

  <lookup-method name="getCurrentSessionBean"
       bean="yourSessionBeanToInitialize"/>
  

• define the interceptor abstract, with an abstract method getCurrentSessionBean()

• create a flag initialized on the bean
• on each interception, call the lookup method and it will return an instance of the bean from the current session. If it is not initialized (the flag), initialize it
• you can also use @PostConstruct and spare the initizlied flag

Another option is to:

• define a HttpSessionListener in web.xml (or with annotations if using servlet 3.0)
• use WebApplicationContextUtils.getRequiredWebApplicationContext(servletContext) to obtain the context
• call getBean(..) to get an instance of the session-scoped bean
• it will be initialized with @PostConstruct at that point

The first option is "more spring", the second is easier and faster to implement.