Configure ServletContext before triggering initialization of ServletContextInitializer beans

[wilkinsona]

We currently configure the ServletContext (init parameters and session cookie configuration) using a pair of ServletContextInitializer beans. We also use ServletContextInitializer beans to register filters and servlets with the container. This means any configuration classes that produce Filter, Servlet, FilterRegistrationBean, ServletRegistrationBean beans are initialized before the init parameters and session cookie configuration has been applied to the ServletContext.

We could, perhaps, resolve this problem by using something other than a ServletContextInitializer to configure the init parameters and session cooke configuration on the servlet context.

[wilkinsona]

The ServletContextInitializers that cause the problem:

• SessionConfiguringInitializer
• InitParameterConfiguringServletContextInitializer

[wilkinsona]

We could pass the init parameters, etc into the ConfigurableServletWebServerFactory and then it could create a ServletContextInitializer of its own that applies the configuration to the ServletContext before the ServletWebServerApplicationContext uses its self initialiser to prepare the web application context and then call all the servlet context initialiser beans.