Spring MappingException: Could not determine type-CodePudding

I am building a Single-Page-Webapp for testing-scenario and i am using spring-jpa. I want to use this JSON data-model for my post-request:

{
  "id": 1,
  "title": "test-title",
  "releaseDate": "2021/12/15",
  "rating" : {
      "stars" : 5,
      "comment" : "very exciting"
   }
}

If i start my application, i get the following error: Caused by: org.hibernate.MappingException: Could not determine type for: de.demo.dto.Rating, at table: books, for columns: [org.hibernate.mapping.Column(rating)]

If i am declaring the class "rating" with @Entity and add the field "id", the application is starting without errors (if i am using an @OneToOne annotation). But for the class "Rating" i do not want to use an own data table with an "id". Can everyone help me with my issues? How do i fix this problem?

Class books:

@Getter
@Setter
@Entity
public class Books {

    @Id
    @GeneratedValue(strategy= GenerationType.AUTO)
    @Column(unique = true, nullable = false)
    private int id;
    private String title;
    private String releaseDate;
    private Rating rating;
}

class Rating

@Getter
@Setter
public class Rating {
    int stars;
    String comment;
}

Thanks!

CodePudding user response：

So seems you want one to one relationship but dont want it to be in another table, best thing comes to my mind is saving that rating as a json object String. So you might need to do cruds with some third party library like GSON:

Gson gson = new Gson(); // Or use new GsonBuilder().create();
MyType target2 = gson.fromJson(json, MyType.class); // deserializes json into target2