CODEWITHSUNDEEP
javaspring-boothibernatedto
user9347049
user9347049

Reputation: 2055

org.hibernate.MappingException: Unknown entity - Hibernate, SpringBoot, DTO pattern

I am trying to build a simple SpringBoot and Hibernate app using DAO and DTO pattern.

I am trying to save a list of users to the database.

When I am using User class it works fine, but when I am trying to use DTO CreateUserDto class I am getting the following error:

"Unknown entity: com.app.sportapp.dto.CreateUserDto; nested exception is org.hibernate.MappingException: Unknown entity: com.app.sportapp.dto.CreateUserDto"

There is a SingleTable inheritance where Player class and Coach class inherit User class.

User.java

@NoArgsConstructor
@AllArgsConstructor
@ToString
@Getter
@Setter
@Entity(name = "Users")
@ApiModel(description = "All details about user")
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name = "User_Type", discriminatorType= DiscriminatorType.STRING)
public class User implements Seriaalizable{

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    private String firstName;   
    private String lastName;    
    private String username;    
    private String email;    
    private String password;   
    private String contactNumber;
}

Player.java

@NoArgsConstructor
@AllArgsConstructor
@ToString
@Getter
@Setter
@Entity(name = "Players")
@DiscriminatorValue(value = "player")
@DiscriminatorOptions(force=true)
public class Player extends User {...}

Coach.java

@Entity(name = "Coaches")
@DiscriminatorValue(value = "coach")
@DiscriminatorOptions(force=true)
public class Coach extends User{

}

And here are DTO's:

CreateUserDto.java

public class CreateUserDto {...}

PlayerDto.java

public class PlayerDto extends CreateUserDto{...}

CoachDto.java

public class CoachDto extends CreateUserDto{


}

As I am very new to DAO and DTO pattern from error I am getting I assume that it is expected to have a model with @Entity called CreateUser so same name as DTO CreateUserDto? Or can I have the example what I did to have a User model and create a new CreateUserDto?

Thanks!

Upvotes: 0

Views: 1267

Answers (1)

Davide D'Alto
Davide D'Alto

Reputation: 8246

The error happens because you are treating a DTO as an entity. Remove the JPA annotations from the DTOs and don't use those classes for connecting to the db.

You will convert the results from your queries from entities to DTO and vice-versa.

I would also suggest to have a look at Mapstruct for the creation of DTO. This will probably make it easier to separate the entities from the DTOs.

Upvotes: 1

Related Questions