How to integrate JAX-RS with CDI in a Servlet 3.0 container
I have a web application running on a Servlet 3.0 container (Jetty 9.0.4) using JSF 2.2 (Mojorra 2.1.3) & CDI 1.1 (Weld 2.0.3). No full-fledged application server is used. In this application I also have a JAX-RS 2.0 (Jersey 2.2) resource class serving REST requests. I have integrated JAXB binding and also JSON marshalling (Jackson 2.2). I use Maven 3.0.5 for the build management. These are the relevant parts of my project setup:
Maven pom.xml:
...
<dependencies>
<!-- Servlet 3.0 API -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<scope>provided</scope>
</dependency>
<!-- Contexts and Dependency Injection for Java EE -->
<dependency>
<groupId>org.jboss.weld.servlet</groupId>
<artifactId>weld-servlet</artifactId>
<version>2.0.3.Final</version>
</dependency>
<!-- JavaServer Faces -->
<dependency>
<groupId>com.sun.faces</groupId>
<artifactId>jsf-api</artifactId>
<version>2.2.2</version>
</dependency>
<dependency>
<groupId>com.sun.faces</groupId>
<artifactId>jsf-impl</artifactId>
<version>2.2.2</version>
</dependency>
<!-- JAX-RS RESTful Web Services -->
<dependency>
<groupId>org.glassfish.jersey.containers</groupId>
<artifactId>jersey-container-servlet</artifactId>
<version>2.2</version>
</dependency>
<!-- JSON Mapping Framework -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.2.2</version>
</dependency>
<dependency>
<groupId>org.glassfish.jersey.media</groupId>
<artifactId>jersey-media-json-jackson</artifactId>
<version>2.2</version>
</dependency>
</dependencies>
...
Deployment Descriptor web.xml:
...
<context-param>
<param-name>javax.faces.PROJECT_STAGE</param-name>
<param-value>Development</param-value>
</context-param>
<servlet>
<servlet-name>Faces Servlet</servlet-name>
<servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>Faces Servlet</servlet-name>
<url-pattern>/jsf/*</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>Jersey REST Service</servlet-name>
<servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
<init-param>
<param-name>javax.ws.rs.Application</param-name>
<param-value>my.package.config.RestApplication</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>Jersey REST Service</servlet-name>
<url-pattern>/rest/*</url-pattern>
</servlet-mapping>
<session-config>
<session-timeout>30</session-timeout>
</session-config>
<listener>
<listener-class>org.jboss.weld.environment.servlet.Listener</listener-class>
</listener>
<listener>
<listener-class>com.sun.faces.config.ConfigureListener</listener-class>
</listener>
<resource-env-ref>
<description>Object factory for the CDI Bean Manager</description>
<resource-env-ref-name>BeanManager</resource-env-ref-name>
<resource-env-ref-type>javax.enterprise.inject.spi.BeanManager</resource-env-ref-type>
</resource-env-ref>
...
JAX-RS root resource class:
@Path("/person")
public class PersonController
{
@Inject
private PersonService personService;
@GET
@Produces({MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML})
public List<Person> getAllPersons()
{
return personService.getAll();
}
@GET
@Path("/{index}")
@Produces({MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML})
public Person getPerson(@PathParam("index") int index)
{
return personService.get(index);
}
@POST
@Consumes({MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML})
public void savePerson(Person person)
{
personService.add(person);
}
}
JAX-RS application configuration:
public class RestApplication extends ResourceConfig
{
public RestApplication()
{
// For JSON binding
register(new JacksonFeature());
register(new ApplicationBinder());
packages("my.package.controller");
}
}
JAX-RS injection binding configuration:
public class ApplicationBinder extends AbstractBinder
{
@Override
protected void configure()
{
// Means something like: bind the field at an injection point of type PersonService to an instance of type PersonService
bind(PersonService.class).to(PersonService.class);
}
}
And finally the JSF managed bean:
@Named
@SessionScoped
public class PersonBean implements Serializable
{
private static final long serialVersionUID = 1L;
@Inject
private PersonService personService;
private Person newPerson = new Person();
public List<Person> getAll()
{
return personService.getAll();
}
public Person getNewPerson()
{
return newPerson;
}
public void setNewPerson(Person newPerson)
{
this.newPerson = newPerson;
}
public Gender[] getGenders()
{
return Gender.values();
}
public String saveNewPerson()
{
personService.add(newPerson);
newPerson = new Person();
return "index";
}
}
At the end, I want to be able to use the same application scoped service instances in the REST resource classes as well as in the JSF beans, but I can't get CDI and JAX-RS work together.
The JSF/CDI part works fine, but the injection into the REST resource classes does not really work. I read some articles, where they showed two different approaches to combine CDI and JAX-RS: The first one is to annotate the REST resource class with @ManagedBean in order for the class to be instantiated by the CDI container and to be managed by the JAX-RS container:
@ManagedBean
@Path("/person")
public class PersonController
{
@Inject
private PersonService personService;
...
The second approach is to give the class a CDI scope, e.g. @RequestScoped in order for the class to be instantiated and managed by the CDI container.
@Path("/person")
@RequestScoped
public class PersonController
{
@Inject
private PersonService personService;
...
None of the approaches work for me. I always end up with the following exception:
org.glassfish.hk2.api.UnsatisfiedDependencyException: There was no object available for injection at Injectee(requiredType=PersonService,parent=PersonController,qualifiers={}),position=-1,optional=false,self=false,unqualified=null,5643079)
at org.jvnet.hk2.internal.ThreeThirtyResolver.resolve(ThreeThirtyResolver.java:74)
at org.jvnet.hk2.internal.ClazzCreator.resolve(ClazzCreator.java:208)
at org.jvnet.hk2.internal.ClazzCreator.resolveAllDependencies(ClazzCreator.java:231)
at org.jvnet.hk2.internal.ClazzCreator.create(ClazzCreator.java:328)
at org.jvnet.hk2.internal.SystemDescriptor.create(SystemDescriptor.java:454)
at org.glassfish.jersey.process.internal.RequestScope.findOrCreate(RequestScope.java:158)
at org.jvnet.hk2.internal.Utilities.createService(Utilities.java:2296)
at org.jvnet.hk2.internal.ServiceLocatorImpl.getService(ServiceLocatorImpl.java:590)
at org.jvnet.hk2.internal.ServiceLocatorImpl.getService(ServiceLocatorImpl.java:577)
at org.glassfish.jersey.internal.inject.Injections.getOrCreate(Injections.java:172)
But this error disappears when changing the injection binding configuration to:
bind(PersonServiceImpl.class).to(PersonService.class);
Now injection somehow works, but for every REST request I get a new instance of the PersonServiceImpl injected, even if this service is application scoped. To me this is an indicator, that the JAX-RS component is totally separated from the CDI stuff and lives in a completely different environment or container as the CDI / JSF stuff does.
So I really wonder how to make these two concepts work together in a pure servlet 3.0 container.
Answer
I solved my problem.
The problem is, that Jersey JAX-RS implementation uses the HK2 dependency injection framework and this framework is simply not aware of the CDI beans. And by following the idea of the accepted answer in this post, I make the CDI beans available for the HK2 injection bindings and the injection of my application scoped beans works fine now.
But I really wonder why it is so cumbersome to bring together two constituent parts of Java EE.
Update: As G. Demecki mentioned in a comment, this is solution is no longer needed! But it helped me out at the time of asking this question.