modelMapper:不能将ObjectiveDto强制转换为类ObjectiveModel

import org.modelmapper.ModelMapper;

public class Main {
    public static void main(String[] args) {
        ModelMapper modelMapper = new ModelMapper();

        ObjectiveDto objectiveDto = new ObjectiveDto();
        objectiveDto.setTitle("Sample Title");
        objectiveDto.setDescription("Sample Description");

        ObjectiveModel objectiveModel = modelMapper.map(objectiveDto, ObjectiveModel.class);

        System.out.println("Title: " + objectiveModel.getTitle());
        System.out.println("Description: " + objectiveModel.getDescription());
    }
}

class ObjectiveDto {
    private String title;
    private String description;

    // getters and setters
    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }
}

class ObjectiveModel {
    private String title;
    private String description;

    // getters and setters
    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }
}