Embeded object is always null? - spring-boot

Question

I have following Request body which I am trying to insert into the database:
{
"vin": "1HGCR2F3XFA027534",
"latitude": 41.803194,
"longitude": -88.144406,
"timestamp": "2017-05-25T17:31:25.268Z",
"fuelVolume": 1.5,
"speed": 85,
"engineHp": 240,
"checkEngineLightOn": false,
"engineCoolantLow": true,
"cruiseControlOn": true,
"engineRpm": 6300,
"tires": {
"frontLeft": 34,
"frontRight": 36,
"rearLeft": 29,
"rearRight": 34
}
}
I cannot insert it as Tires object is always mapped as null. I don't think the json object is able to map to tires object.
Here are snippets
In controller:
#RequestMapping(method = RequestMethod.POST, value = "/readings")
public void readVehicleStatus(#RequestBody VehicleStatus vehicleStatus){
vehicleStatusService.readVehicleStatus(vehicleStatus);
}
VehicleStatus.java
#Entity
public class VehicleStatus {
#Id
private String vin;
private Double latitude;
private Double longitude;
private Double fuelVolume;
private int speed;
private int engineHp;
private int engineRpm;
private boolean checkEngineLightOn;
private boolean engineCoolantLow;
private boolean cruiseControlOn;
#Embeded
private Tires tires;
/* getters and setters created */
}
Tires.java
#Embeddable
public class Tires {
#Id
#GeneratedValue(strategy= GenerationType.IDENTITY)
int id;
private int frontLeft;
private int frontRight;
private int rearLeft;
private int rearRight;
/* getters and setters included */
}

Answer 1

In your VehicleStatus the tires json property is named vehicleTire but in the json is named tires, that's why is always null, so you should add #JsonProperty(value="tires").
Here is the full code:
#Entity
public class VehicleStatus implements Serializable{
#Id
private String vin;
private Double latitude;
private Double longitude;
private Double fuelVolume;
private int speed;
private int engineHp;
private int engineRpm;
private boolean checkEngineLightOn;
private boolean engineCoolantLow;
private boolean cruiseControlOn;
#OneToOne(mappedBy = "vehicleStatus",cascade=CascadeType.ALL)
#JoinColumn(name = "id")
#JsonProperty(value="tires") // here is the key :)
private Tires vehicleTire;
// Getters && Setters
}
#Entity
public class Tires implements Serializable{
#Id
#GeneratedValue(strategy= GenerationType.IDENTITY)
Integer id;
private Integer frontLeft; // NB try always to use wrapper type rather than primitive in jpa
private Integer frontRight;
private Integer rearLeft;
private Integer rearRight;
#OneToOne
private VehicleStatus vehicleStatus;
// Getters && Setters
}
TiresRepository:
public interface TiresRepository extends JpaRepository<Tires, Integer>{
}
VehicleStatusRepository:
public interface VehicleStatusRepository extends JpaRepository<VehicleStatus, String>{
}
Example of controller :
#RestController
#RequestMapping
class MyController {
#Autowired
private VehicleStatusRepository vehicleStatusRepository;
#RequestMapping(method = RequestMethod.POST, value = "/readings")
public void readVehicleStatus(#RequestBody VehicleStatus vehicleStatus){
vehicleStatusRepository.saveAndFlush(vehicleStatus);
}
}
Main class :
#SpringBootApplication
#EnableAutoConfiguration
public class SpringStackOverflowSolutionApplication {
public static void main(String[] args) {
SpringApplication.run(SpringStackOverflowSolutionApplication.class, args);
}
}
NB: do not forget cascadeAll, else the tires object will not be saved in the database and you will get the following exception :
org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : package.VehicleStatus.vehicleTire -> package.Tires