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i am using tomcat 9.0.4 and Java 1.8. In the same project, jersey is providing an webservice. I can use @Inject from the webservice classes without any problem. I am trying to get injection working from my websocket endpoint display below.

@ApplicationScoped
@ServerEndpoint("/endpoint")
public class ArchApi {

  @Inject RepClass injectedClass;

  @OnMessage()
  public String onMessage(byte[] data) {
       injectedClass.doThings("test");
  }

}

This is my CDI implementation: 

    <dependency>
        <groupId>org.glassfish.jersey.inject</groupId>
        <artifactId>jersey-hk2</artifactId>
        <version>2.27</version>
    </dependency>

All i get is a java.lang.NullPointerException.

I found this feature request. So i think Injection is still not implemented in tomcat.

My questions:

  • How do i proper write my incomming data to my repository?
  • Is there another way to get Injection working?

At the moment i am thinking about a migration to glassfish, which should support injection from a Serverendpoint

Mr Mueseli
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1 Answers1

4

You could use the following configurator to make CDI manage the endpoint classes:

public class CdiAwareConfigurator extends ServerEndpointConfig.Configurator {

    public <T> T getEndpointInstance(Class<T> endpointClass) throws InstantiationException {
        return CDI.current().select(endpointClass).get();
    }
}

Then annotate your endpoint classes as following:

@ServerEndpoint(value = "/chat", configurator = CdiAwareConfigurator.class)
public class ChatEndpoint {
    ...
}

Depending on your CDI configuration, you may need to annotate the endpoint classes with @Dependent.

Alternatively you could programmatically look up for a bean instance using:

SomeSortOfBean bean = CDI.current().select(SomeSortOfBean.class).get();
cassiomolin
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  • Thanks, injection works now (: But i can´t create an entityManagerFactory. is it something related? – Mr Mueseli Jul 04 '18 at 16:18
  • @MrMueseli It may not be related, but it's hard to say with the level of details you provided in your question. If my answer works for you, please accept it and add the relevant details in a new question. – cassiomolin Jul 04 '18 at 16:29