Access Spring beans from a servlet in JBoss

I want to write a simple servlet in JBoss which will call a method on a Spring bean. The purpose is to allow a user to kick off an internal job by hitting a URL.

What is the easiest way to get hold of a reference to my Spring bean in the servlet?

JBoss web services allow you to inject a WebServiceContext into your service class using an @Resource annotation. Is there anything comparable that works in plain servlets? A web service to solve this particular problem would be using a sledgehammer to crush a nut.

From stackoverflow

• I've found one way to do it:

  WebApplicationContext context = WebApplicationContextUtils.getWebApplicationContext(getServletContext());
  SpringifiedJobbie jobbie = (SpringifiedJobbie)context.getBean("springifiedJobbie");
  

• Your servlet can use WebApplicationContextUtils to get the application context, but then your servlet code will have a direct dependency on the Spring Framework.

  Another solution is configure the application context to export the Spring bean to the servlet context as an attribute:

  <bean class="org.springframework.web.context.support.ServletContextAttributeExporter">
    <property name="attributes">
      <map>
        <entry key="jobbie" value-ref="springifiedJobbie"/>
      </map>
    </property>
  </bean>
  

  Your servlet can retrieve the bean from the servlet context using

  SpringifiedJobbie jobbie = (SpringifiedJobbie) getServletContext().getAttribute("jobbie");
  

  Sophie Tatham : Nice, thank you.

  Elliot : What is the advantage to doing it this way and not using WebApplicationContextUtils? Either way it's tied to Spring.

  Jim Huang : The mechanism to populate the servlet context attribute does not have to be implemented using Spring. A filter or another servlet that runs at startup can populate the servlet context attribute.

• There is a much more sophisticated way to do that. There is SpringBeanAutowiringSupportinside org.springframework.web.context.support that allows you building something like this:

  public class MyServlet extends HttpServlet {
  
    @Autowired
    private MyService myService;
  
    public void init(ServletConfig config) {
      SpringBeanAutowiringSupport.processInjectionBasedOnServletContext(this,
        config.getServletContext());
    }
  }
  

  This will cause Spring to lookup the ApplicationContext tied to that ServletContext (e.g. created via ContextLoaderListener) and inject the Spring beans available in that ApplicationContext.