How to get access to ServletContext inside of an @Configuration or @SpringBootApplication class

问题

I'm attempting to update an old Spring application. Specifically, I'm trying to pull all of the beans out of the old xml-defined form and pull them into a @SpringBootApplication format (while dramatically cutting down on the overall number of beans defined, because many of them did not need to be beans). My current issue is that I can't figure out how to make the ServletContext available to the beans that need it.

My current code looks something like this:

package thing;

import stuff

@SpringBootApplication
public class MyApp {

    private BeanThing beanThing = null;

    @Autowired
    private ServletContext servletContext; 

    public MyApp() {
        // Lots of stuff goes here.
        // no reference to servletContext, though
        // beanThing gets initialized, and mostly populated.
    }

    @Bean public BeanThing getBeanThing() { return beanThing; }

    @PostConstruct
    public void populateContext() {
        // all references to servletContext go here, including the
        // bit where we call the appropriate setters in beanThing
    }
}

The error I get back: Field servletContext in thing.MyApp required a bean of type 'javax.servlet.ServletContext' that could not be found.

So... what am I missing? Is there something I'm supposed to be adding to the path? Is there some interface I need to implement? I can't provide the bean myself because the whole point is that I'm trying to access servlet context info (getContextPath() and getRealPath() strings) that I don't myself have.

回答1:

Please be aware of the best practice for accessing the ServletContext: You shouldn't do it in your main application class, but e. g. a controller.

Otherwise try the following:

Implement the ServletContextAware interface and Spring will inject it for you.

Remove @Autowired for the variable.

Add setServletContext method.

@SpringBootApplication
public class MyApp implements ServletContextAware {

    private BeanThing beanThing = null;

    private ServletContext servletContext; 

    public MyApp() {
        // Lots of stuff goes here.
        // no reference to servletContext, though
        // beanThing gets initialized, and mostly populated.
    }

    @Bean public BeanThing getBeanThing() { return beanThing; }

    @PostConstruct
    public void populateContext() {
        // all references to servletContext go here, including the
        // bit where we call the appropriate setters in beanThing
    }

    public void setServletContext(ServletContext servletContext) {
        this.context = servletContext;
    }


}

来源：https://stackoverflow.com/questions/50047521/how-to-get-access-to-servletcontext-inside-of-an-configuration-or-springbootap