Can we Convert more than one entity into single Dto in Spring boot - spring

Question

Can we Convert More Than One Entity into single DTO
I have two entity Car And Truck and I want to pass single Entity VehcileDto on Thymleaf page is it possible or not?

Answer 1

That's not necessarily a Spring Boot topic but rather a Java topic.
Say you got the following classes:
/**
* In this class you would define the Car Entity with all its fields and relations
*/
public class CarEntity {
private String someCarField;
private String anotherCarField;
public String getSomeCarField() {
return someCarField;
}
public void setSomeCarField(String someCarField) {
this.someCarField = someCarField;
}
public String getAnotherCarField() {
return anotherCarField;
}
public void setAnotherCarField(String anotherCarField) {
this.anotherCarField = anotherCarField;
}
}
Your Truck Entity would look very similar.
Then you define a DTO:
/**
* Here you would define the DTO. The DTO is just two Entities in one WrapperObject (See Definition of DTO in Java).
* This includes all the fields you want to use on your thymeleaf UI.
* This is the DTO you would put into your model using the MVC Controller
*/
public class VehicleDTO {
private String someTruckField;
private String anotherTruckField;
private String someCarField;
private String anotherCarField;
public VehicleDTO(String someTruckField, String anotherTruckField, String someCarField, String anotherCarField) {
this.someTruckField = someTruckField;
this.anotherTruckField = anotherTruckField;
this.someCarField = someCarField;
this.anotherCarField = anotherCarField;
}
}
This is a class that contains both Entities.
Then you would need a factory to properly create the DTO:
/**
* This is a Factory class which creates a VehicleDTO
*/
public class VehicleDTOFactory {
public VehicleDTO createVehicleDTO(CarEntity car, TruckEntity truck){
return new VehicleDTO(truck.getSomeTruckField(),
truck.getAnotherTruckField(),
car.getSomeCarField(),
car.getAnotherCarField());
}
}
Then over the MVC controller you would call the factory Method and fill the parameters with Entities from your database.
This is just a very basic example.
I'd recommend looking closer into why Factories and DTOs are used