AEM6.4 @Reference not working in SlingServlet | Community
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pradeepdubey82
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April 1, 2019
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AEM6.4 @Reference not working in SlingServlet

  • April 1, 2019
  • 23 replies
  • 24983 views

Hi  All,

My sling servlet is not working as soon as i add

@Reference in it, otherwise it works fine

Below is the servlet code, i have create custom configuration as per the AEM6.4 standards(one @Interface class, one Interface class, one Impl class with proper annotations(org.osgi.service.component.annotations))

@Component(service = Servlet.class,

property = { Constants.SERVICE_DESCRIPTION + "=Simple Demo Servlet",

"sling.servlet.methods=" + HttpConstants.METHOD_GET,

"sling.servlet.paths=" + "/bin/testservlet" }

)

public class TestServlet extends SlingAllMethodsServlet {

  private static final long serialVersionUID = 1L;

 

  @Reference

  MySimpleService mySimpleService;

 

  private static final Logger logger =

  LoggerFactory.getLogger(TestServlet.class);

 

  @Override

  protected void doGet(final SlingHttpServletRequest req, final

  SlingHttpServletResponse resp) throws ServletException, IOException {

  logger.info("Inside doGet!!!");

  try {

  logger.info("Name ::: "+mySimpleService.getMyName());

  resp.getWriter().write(mySimpleService.getMyName()); }

  catch(Exception ex) {

  logger.error("Error in  doGet ::: ", ex);

  }

  }

}

 

Please advise, any help is highly appreciated.

Thanks,

Pradeep

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    Best answer by smacdonald2008

    Look at our SOLR Article. This one closely matches your requirement. We have a class named MySimpleService that reads OSGi config values.

    In the Servlet in this article - we use a @Refence to get config values:

    @Reference

        SolrServerConfiguration solrConfigurationService;

    This shows the proper way of getting OSGI configuration information within an AEM Servlet. Never try and read OSGI config information directly from a servlet. Write a separate class - as shown in this development article.

    Adobe Experience Manager Help | Integrating SOLR with Adobe Experience Manager 6.4

    Hope this clear this issue up. Notice the Java code in this Servlet. We use the CONFIG values to perform SOLR actions - such as getting the URL to the SOLR server.

                final String protocol = solrConfigurationService.getSolrProtocol();

            final String serverName = solrConfigurationService.getSolrServerName();

            final String serverPort = solrConfigurationService.getSolrServerPort();

            final String coreName = solrConfigurationService.getSolrCoreName();

            final String pagesResourcePath = solrConfigurationService

    I would go through this entire article so you understand.

    Hope this helps you.

    23 replies

    Show previous replies
    P
    pradeepdubey82Author
    New Participant
    April 2, 2019

    I followed the same link, not working in  sling servlet.

    smacdonald2008
    smacdonald2008
    New Participant
    April 2, 2019

    Following article shows how to read OSGi config values - notice this class is not a Sling Servlet:

    Reading OSGi Configuration Values for Adobe Experience Manager 6.3

    smacdonald2008
    smacdonald2008
    New Participant
    April 2, 2019

    That may be where your issue is. I would not try to mix that up.

    I would create a separate class that reads those OSGi conig values. Then from your Sling Servlet - you can create an instance of that class and invoke a method to get the config values.

    P
    pradeepdubey82Author
    New Participant
    April 2, 2019

    Hi Hemant arora tried your way also, didn't work.

    P
    pradeepdubey82Author
    New Participant
    April 2, 2019

    Hi Donald,

    My requirement is to read custom configuration properties from osgi console in sling servlet using AEM6.4 SP2.

    The example you shared is just to define and use the class in @Reference. I didn't find any custom configuration.

    Thanks,

    Pradeep

    smacdonald2008
    smacdonald2008
    New Participant
    April 2, 2019

    See this article - where we used @Reference in a SLing Servlet:

    Adobe Experience Manager Help | Querying Adobe Experience Manager 6.4 JCR data using the QueryBuilder API

    Hemant_arora
    Hemant_arora
    New Participant
    April 2, 2019

    This should work.

    ____________________________________________________________________________________________________

    import org.osgi.service.metatype.annotations.AttributeDefinition;

    import org.osgi.service.metatype.annotations.ObjectClassDefinition;

    @ObjectClassDefinition(name = "My Service Configuration", description = "Service Configuration")

    public @interface CustomConfigIntf {

    @AttributeDefinition(name = "Test Namel", defaultValue="Pradeep", description = "Read my name")

        String name();

    }

    ______________________________________________________________________________________________________

    public interface MySimpleService {

    public String getName();

    }

    ______________________________________________________________________________________________________

    import org.osgi.service.component.annotations.Activate;

    import org.osgi.service.component.annotations.Component;

    import org.osgi.service.metatype.annotations.Designate;

    import com.aem.test.core.CustomConfigIntf;

    import com.aem.test.core.service.MySimpleService;

    @Component(service=MySimpleService.class, configurationPolicy=ConfigurationPolicy.REQUIRE)

    @Designate(ocd = CustomConfigIntf.class)

    public class MySimpleServiceImpl implements MySimpleService {

    private CustomConfigIntf configs;

    @Activate

    public void activate(CustomConfigIntf config) {

    this.configs = config;

    }

    public String getName() {

    return configs.name();

    }

    }

    P
    pradeepdubey82Author
    New Participant
    April 2, 2019

    Hi Donald,

    Below is my entire code

    import org.osgi.service.metatype.annotations.AttributeDefinition;

    import org.osgi.service.metatype.annotations.ObjectClassDefinition;

    @ObjectClassDefinition(name = "My Service Configuration", description = "Service Configuration")

    public @interface CustomConfigIntf {

    @AttributeDefinition(name = "Test Namel", defaultValue="Pradeep", description = "Read my name")

        String name();

    }

    public interface MySimpleService {

    public String getName();

    }

    import org.osgi.service.component.annotations.Activate;

    import org.osgi.service.component.annotations.Component;

    import org.osgi.service.component.annotations.ConfigurationPolicy;

    import org.osgi.service.metatype.annotations.Designate;

    @Component(service=MySimpleService.class, configurationPolicy=ConfigurationPolicy.REQUIRE)

    @Designate(ocd = CustomConfigIntf.class)

    public class MySimpleServiceImpl implements MySimpleService {

    private CustomConfigIntf config;

       

        private String name;

        @Activate

        public void activate(CustomConfigIntf config) {

            this.config = config;

            this.name = config.name();

        }

        public String getName() {

            return this.name;

        }

        

    }

    Let me know where i am doing wrong?

    @Referencce is not working in servlet.

    Thanks,

    Pradeep

    Hemant_arora
    Hemant_arora
    New Participant
    April 2, 2019

    In your service class MySimpleService  check the @component annotation:

    @Component(service = MySimpleService.class, immediate = true)

    Go to http://localhost:4502/system/console/components and search for MySimpleService . Check the status of the service.

    P
    pradeepdubey82Author
    New Participant
    April 2, 2019

    Yes, My bundle is in active state, and servlet is unsatisfied state due to @Reference

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