如何获取Web应用程序的上下文实例。 背景？

Question

I don't know exactly how to get the web application ctx. instance within a Spring web application. For ex We usually do the configuration like :

@EnableWebMvc
public class WebConfig extends WebMvcConfigurerAdapter {
...
}

I'm aware of the ApplicationContextAware, I've implemented it before. The thing is it was implemented to get the Application context and not specifically Web application context. For ex :

public class ApplicationContextProvider implements ApplicationContextAware{
    private static ApplicationContext context;
    public static ApplicationContext getApplicationContext() {
        return context;
    }

    @Override
    public void setApplicationContext(ApplicationContext ac)
            throws BeansException {
        context = ac;
    }
}

And later in handler/controller classes I obtained it with smtg like this :

MrBean tb = ApplicationContextProvider.getApplicationContext().getBean("MrBean", MrBean.class);

In this ex the context is not a web app. context rather than a global app. context (not specifically a web context). I need your help in retrieving the web context instance because I need to active some profiling beans already configured from the configuration. Thanks in advance.

Answer 1

If you have the HttpServletRequest object you can retrieve the WebApplicationContext via RequestContextUtils#findWebApplicationContext()

Look for the WebApplicationContext associated with the DispatcherServlet that has initiated request processing, and for the global context if none was found associated with the current request. The global context will be found via the ServletContext or via ContextLoader's current context.

NOTE: This variant requires Servlet 3.0+ and is generally recommended for forward-looking custom user code.

Eg

WebApplicationContext webApplicationContext = RequestContextUtils.findWebApplicationContext(request);

But this only works within spring mvc/webflow context because the Spring DispatcherServlet ensures that the WebApplicationContext instance is available in the currently running thread.