Autowiring in servlet

Question

i want to use spring autowiring in servlet so here's my code:

@Configurable
public class ImageServlet extends HttpServlet {

   @Autowired
   private SystemPropertyDao systemPropertyDao;

   @Override
   public void init() throws ServletException {


   String imagePath = systemPropertyDao.findByID(StaticParam.CONTENT_FOLDER);

}

while the SystemPropertyDao is annotated with @Repository

and my applicationContext.xml:

<context:component-scan base-package="com.basepackage" />
<mvc:annotation-driven />
<context:annotation-config />
<context:spring-configured/>

web.xml:

  <servlet>
    <servlet-name>imageServlet</servlet-name>
    <servlet-class>com.xeno.basepackage.ImageServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>imageServlet</servlet-name>
    <url-pattern>/myimages/*</url-pattern>
  </servlet-mapping>

sometimes the autowiring works and sometimes it doesn't (the reference to the spring bean systemPropertyDao is null), can anyone please tell me if i am missing something?

What do you mean by "autowiring doesn't work"? It doesn't work in specific methods for example? — Boris Treukhov, Aug 07 '12 at 10:22
@Boris Treukhov (the reference to the spring bean systemPropertyDao is null) — Mahmoud Saleh, Aug 07 '12 at 10:27
Forgive me my ignorance(somewhat like in the deleted answer) but what is the actual mechanism are you using for injection? Do you call SpringBeanAutowiringSupport.processInjectionBasedOnServletContext() anywhere? — Boris Treukhov, Aug 07 '12 at 10:40
If you configured the servlet in web.xml there might be more than one instance of it. — Stefan, Aug 07 '12 at 10:43
@Stefan Lindenberg, yes i did configured the servlet in web.xml, please see my the updated question, any ideas how to solve this case ? — Mahmoud Saleh, Aug 07 '12 at 10:45
@Msaleh There not many ways to access Spring beans from the servlet class (http://stackoverflow.com/questions/467235/access-spring-beans-from-a-servlet-in-jboss) so it's interesting which way you've chosen. In the simplest case you may be trying to access the bean before calling SpringBeanAutowiringSupport.processInjectionBasedOnServletContext so it's null. — Boris Treukhov, Aug 07 '12 at 10:50

score 78 · Accepted Answer · edited May 23 '17 at 11:46

78

I followed the solution in the following link, and it works fine: Access Spring beans from a servlet in JBoss

public class MyServlet extends HttpServlet {

  @Autowired
  private MyService myService;

  public void init(ServletConfig config) {
    super.init(config);
    SpringBeanAutowiringSupport.processInjectionBasedOnServletContext(this,
      config.getServletContext());
  }
}

edited May 23 '17 at 11:46

Community

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answered Aug 07 '12 at 11:17

Mahmoud Saleh

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thanks very much. At first I use `Resource` annotation, it doesn't work, and `Autowired` works well. – hiway Oct 05 '13 at 07:13
Thank you very much, but why they specifically mentioned in jBoss?? Won't it work in weblogic?? – Suryaprakash Pisay Aug 13 '14 at 13:46
It will work in Weblogic and even in Tomcat ! This is only the title of the documentation: the solution is actually relying upon the standard servlet api and pure Spring classes. – Chucky Apr 01 '15 at 08:49

Stefan · Answer 2 · 2014-08-14T08:58:36.290

28

Remove the @Configurable annotation from your servlet and add:

SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext (this);

at the first line of your init() method.

edited Aug 14 '14 at 08:58

answered Aug 07 '12 at 11:14

Stefan

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Autowiring in servlet

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