Spring Deserialize manytomany table with extra column

I have a manytomany relation mapped with a custom table to add an extra column. I can deserialize it, but deserialized it shows the elements of the join table, I would to just the joined element. So what I currently get is the following:

{
    "id": 122,
    "materials": [
        {
            "id": {
                "materialId": 162,
                "homeworkId": 122
            },
            "position": 1
        },
        {
            "id": {
                "materialId": 163,
                "homeworkId": 122
            },
            "position": 1
        }
    ]
}

I would rather get something like this:

{
    "id": 122,
    "materials": [
        162, 163
    ]
}

I am using standard Spring mapper to deserialize:

@GetMapping("/api/homework/get")
public Homework getHomework(@RequestParam Long id) {
    return homeworkService.findById(id).orElseThrow(HomeworkNotFoundException::new);
}

I have the following java classes (omitted unnecessary methods and functions)

Material

@Getter @Setter @NoArgsConstructor
@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "typeName")
@JsonIdentityInfo(scope = Material.class, generator = ObjectIdGenerators.PropertyGenerator.class, property = "id")
@JsonSubTypes({
        @JsonSubTypes.Type(value = FileMaterial.class, name = "fileMaterial"),
        @JsonSubTypes.Type(value = LinkMaterial.class, name = "linkMaterial")
})

@Entity
@Table(name="material")
@Inheritance(strategy = InheritanceType.JOINED)
public class Material implements FileOwner {
    private static final String sequenceName = "material_id_sequence";

    @Id
    @Column(nullable = false)
    @SequenceGenerator(allocationSize=10,  sequenceName=sequenceName, name=sequenceName)
    @GeneratedValue(generator=sequenceName, strategy=GenerationType.SEQUENCE)
    protected Long id;

    @OneToMany(mappedBy = "material", cascade = CascadeType.ALL, orphanRemoval = true)
    @Fetch(value = FetchMode.SUBSELECT)
    @JsonManagedReference
    List<HomeworkMaterial> homeworks = new ArrayList<>();

}

Homework

@Getter @Setter @NoArgsConstructor
@JsonIdentityInfo(scope = Homework.class, generator = ObjectIdGenerators.PropertyGenerator.class, property = "id")
@Entity
@Table(name = "homework")
public class Homework {
    private static final String sequenceName = "homework_id_sequence";

    @Id
    @Column(nullable = false)
    @SequenceGenerator(allocationSize=10,  sequenceName=sequenceName, name=sequenceName)
    @GeneratedValue(generator=sequenceName, strategy= GenerationType.SEQUENCE)
    protected Long id;

    @OneToMany(mappedBy = "homework", cascade = CascadeType.ALL, orphanRemoval = true)
    @Fetch(value = FetchMode.SUBSELECT)
    @JsonManagedReference
    List<HomeworkMaterial> materials = new ArrayList<>();
}

HomeworkMaterial

@Getter @Setter @NoArgsConstructor
@Entity
@Table(name = "homework_material")
public class HomeworkMaterial {
    @EmbeddedId
    private HomeworkMaterialId id;

    @ManyToOne(fetch = FetchType.LAZY)
    @MapsId("materialId")
    @JsonBackReference
    private Material material;

    @ManyToOne(fetch = FetchType.LAZY)
    @MapsId("homeworkId")
    @JsonBackReference
    private Homework homework;

    @Column(nullable = false)
    private int position;

    public HomeworkMaterial(Material material, Homework homework, int position) {
        this.material = material;
        this.homework = homework;
        this.position = position;
        this.id = new HomeworkMaterialId(material.getId(), homework.getId());
    }
}

HomeworkMaterialId

@Embeddable
@NoArgsConstructor @AllArgsConstructor @Getter @Setter
public class HomeworkMaterialId implements Serializable {

    @Column(name = "material_id")
    private long materialId;

    @Column(name = "homework_id")
    private long homeworkId;
}

For standard @manytomany mappings I was able to achieve this behaviour with @jsonignoreproperties but i can not transfer it to custom join-tables.

Thanks in advance!