实体

// Lombok annotations
public class Plan {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(updatable = false, nullable = false)
    private UUID id;

    private LocalDateTime createdAt;

    @OneToMany
    @JoinColumn
    private Set<AbsractTask> abstractTasks = new TreeSet<>();
}

// Lombok annotations
public class AbstractTask implements Comparable<AbstractTask> {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(updatable = false, nullable = false)
    private UUID id;

    @Column(name = "type", insertable = false, updatable = false)
    protected String type = this.getClass().getSimpleName().toLowerCase();

    private LocalDateTime createdAt;

    private Integer customOrder;
}

// Lombok annotation
public class TextTask extends AbstractTask {
    private String text;

    private Boolean completed;
}

// Lombok annotations
public class NumericalTask extends AbstractTask {

    int current;

    int target;
}

DTO公司

// Lombok annotations
public class PlanDto {

    private UUID id;

    private LocalDateTime createdAt;

    private Set<AbstractTaskDto> tasks;
}

// Lombok annotations
@JsonTypeInfo(
        use = JsonTypeInfo.Id.NAME,
        property = "type")
@JsonSubTypes({
        @Type(value = TextTaskDto.class),
        @Type(value = NumericalTaskDto.class)})
public class AbstractTaskDto {
    private UUID id;

    protected String type = this.getClass().getSimpleName().toLowerCase();

    private LocalDateTime createdAt;

    private Integer customOrder;

// Lombok annotations
public class TextTaskDto extends AbstractTaskDto {
    private String text;

    private Boolean completed;
}

// Lombok annotations
public class NumericalTaskDto extends AbstractTaskDto {
    private int current;

    private int target;
}

制图器

@AllArgsConstructor
public class PlanMapper {

    private final static ModelMapper modelMapper = new ModelMapper();

    public static PlanDto convertToDto(Plan plan) {
        modelMapper.typeMap(Plan.class, PlanDto.class);
        modelMapper.getConfiguration().setPropertyCondition(Conditions.isNotNull());

        return modelMapper.map(plan, planDto.class);
    }
}

发生什么事了
我将jackson与spring boot结合使用，最终，我希望看到我的控制器对一段时间的json响应 Plan 对象类似于：

{
  "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "createdAt": "2021-01-04T07:38:53.362Z",
  "tasks": [
    {
      "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "type": "textTask",
      "createdAt": "2021-01-04T07:38:53.362Z",
      "customOrder": 1,
      "text": "string",
      "completed": false
    },
    {
      "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "type": "numericalTask",
      "createdAt": "2021-01-04T07:38:53.362Z",
      "customOrder": 2,
      "current": 0,
      "target": 5
    }
  ]
}

也就是说，在相应的json列表中存在各种子类型（api的使用者可以使用 type 字段作为 predicate 来确定如何处理元素）。然而，我看到的是json列表（和dto）的元素 Set 简化为抽象的父对象。例如

{
  "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "createdAt": "2021-01-04T07:38:53.362Z",
  "tasks": [
    {
      "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "type": "textTask",
      "createdAt": "2021-01-04T07:38:53.362Z",
      "customOrder": 1
    },
    {
      "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "type": "numericalTask",
      "createdAt": "2021-01-04T07:38:53.362Z",
      "customOrder": 2
    }
  ]
}

对于包含抽象元素集合（也有相应的dto类）的实体，是否有方法配置modelmapper以在从实体到dto的Map过程中维护特定于子级的字段？