JAX-RS REST service implementation in EJB J2EE - rest

Question

Looking for a an example of using JAX-RS to implement an EJB 3 REST service. Would like to have the transactional functionality of EJB and be able to call the EJB from other J2EE apps as well as from AJAX apps (web, mobile, etc).

Answer 1

Service implemented as a stateless session bean. Used a singleton bean to simulate a DAO for illustration purposes.
 
PUT example:
http://mydomain/MyApp/rest/carbean/savecarorder
ContentType:    application/json
JSON:                    {"equipmentId":"570674","status":"L","operation":"PS"}
 
GET example (after the PUT operation to insert or update):
http://mydomain/MyApp/rest/carbean/getcarorder?equipmentId=570674
Results:                {"status":"L","operation":"PS","equipmentId":"570674"}
package com.samnunnally.services;
import javax.ejb.EJB;
import javax.ejb.LocalBean;
import javax.ejb.Stateless;
import javax.ws.rs.Consumes;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.PUT;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.QueryParam;
import javax.ws.rs.core.MediaType;
import com.samnunnally.CarManager;
import com.samnunnally.CarOrder;
/**
* Session Bean implementation class CarService
*/
#Stateless(mappedName = "ejb/CarService")
#LocalBean
#Path ("/carbean")
public class CarService {
#EJB
CarManager carManager;
#GET
#Produces({ MediaType.APPLICATION_JSON })
#Path("/getcarorder")
public CarOrder getCar(#QueryParam("equipmentId") String equipmentId) {
return carManager.getCarOrder(equipmentId);
}
#Path("/savecarorder")
#PUT
#Consumes({ "application/xml", "application/json" })
public String saveCarOrder(CarOrder carOrder) {
carManager.saveCarOrder(carOrder);
return "true";
}
}
This needed to added to the web.xml file of the war file in the ear:
<servlet>
<servlet-name>javax.ws.rs.core.Application</servlet-name>
</servlet>
<servlet-mapping>
<servlet-name>javax.ws.rs.core.Application</servlet-name>
<url-pattern>/rest/*</url-pattern>
</servlet-mapping>
Manager to simulate data layer
package com.samnunnally.managers;
import java.util.HashMap;
import java.util.Map;
import javax.ejb.LocalBean;
import javax.ejb.Singleton;
import com.samnunnally.model.CarOrder;
/**
* Session Bean implementation class CarManager
*
* #author Sam Nunnally
*
*/
#Singleton(mappedName = "ejb/CarManager")
#LocalBean
public class CarManager {
/*
* this should be a database of some sort
*/
private Map<String, CarOrder> carOrders = null;
public CarOrder getCarOrder(String equipmentId) {
return getCarOrders().get(equipmentId);
}
public void saveCarOrder(CarOrder carOrder) {
getCarOrders().put(carOrder.getEquipmentId(), carOrder);
}
private Map<String, CarOrder> getCarOrders(){
if(carOrders == null){
carOrders = new HashMap<String, CarOrder>();
}
return carOrders;
}
}