How to access an OSGI service from a servlet?

[jayv25585659]

II have a servlet (example" localhost:4502/bin/my-servlet-here) where I would need to access an OSGI service.

I've tried several stuff I saw online but I cannot get access/reference to the OSGI service from my servlet.

Any ideas on how it can be done?

In the code servlet class below, I was debugging in my IDE (IntelliJ) and it's hanging/not responding on the line that starts with "ServiceReference reference"

Thanks

-----------

my servlet class

package com.myhost.core.servlets;
import com.myhost.core.services.MyService;
import javax.annotation.Resource;
import javax.inject.Inject;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import org.apache.felix.scr.annotations.sling.SlingServlet;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.SlingHttpServletResponse;
import org.apache.sling.api.servlets.SlingAllMethodsServlet;
import org.apache.sling.commons.json.JSONException;
import org.apache.sling.commons.json.JSONObject;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;
@SlingServlet(paths = "/bin/myservlet", methods = "GET", metatype = true)
public class MyServlet extends SlingAllMethodsServlet {
    @Resource(name="BundleContext")
    private BundleContext context;
    @Override
    protected void doGet(SlingHttpServletRequest request, SlingHttpServletResponse response) throws ServletException, IOException {
    ServiceReference reference = context.getServiceReference(MyService.class.getName());
    MyService service = (MyService)context.getService(reference);
    response.setCharacterEncoding("UTF-8");
    response.setContentType("application/json;charset=UTF-8");
    // the code the populates the JSON variable has been taken out
    printWriter.write(jsonObject.toString());
}

---------

my service class

package com.myhost.core.services;
public interface MyService {
    String getPassword(String type);
}

---------

my service class implementation

package com.myhost.core.services.impl;
import com.myhost.core.services.MyService;
import org.apache.felix.scr.annotations.Activate;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Property;
import org.apache.felix.scr.annotations.Service;
import org.apache.sling.commons.osgi.PropertiesUtil;
import java.util.Map;
@Service
@Component(metatype = true, label = "My Service Implementation")
public class MyServiceImpl implements MyService {
    @Property(label = "property1")
    private static final String Property1 = "com.myhost.core.services.MyService.property1";
    private String property1;
    @Property(label = "property2")
    private static final String Property2 = "com.myhost.core.services.MyService.property2";
    private String property2;
    @Activate
    protected void activate(Map<String, Object> properties) {
        this.property1 = PropertiesUtil.toString(properties.get(Property1), null);
        this.property2 = PropertiesUtil.toString(properties.get(Property2), null);
    }
    @Override
    public String getProperty(int temp) {
        switch (temp) {
            case 1:
                return property1;
            case 2:
                return property2;
            default:
                return "";
        }
    }
}

[Gaurav-Behl]

It seems that you want to use R4 for this implementation..

Did you try using @Reference annotation in servlet?

@Reference

private MyService myService;

Add immediate=true in service

1. @Component(metatype = true, label = "My Service Implementation", immediate=true) 

you may not need the following lines unless you have a specific requirement:

1. @Resource(name="BundleContext") 
2.     private BundleContext context; 
3. ServiceReference reference = context.getServiceReference(MyService.class.getName()); 
4.     MyService service = (MyService)context.getService(reference); 

[jayv25585659]

I did try @reference also (didn't write that in the original post) and service variable was null. But I also didn't have immediate=true. Trying your suggestion now.

[arunpatidar]

If you don't want to use this service outside bundle then remove @Service   annotation from MyServiceImpl and use @Reference annotation as suggested by Gaurav.

@Reference

private MyService myService;