Java Spring projection inside projection

问题

Is it possible to use a projection and in some related object use it's own projection?

For example, a have Exam, that has List<Question>. I'd like to request a list of exams (wich I have a @projection), but I'd like to define the attributes to be retreived for each related Question

回答1:

If I understand correctly you want to use Projection as children of Projection. If it is the case, yes, you can. You can create a QuestionProjection and use inside the ExamProjection.

Example:

@Projection(name = "questionProjection", types = { Question.class }) 
public interface QuestionProjection {
    // Getters
}

@Projection(name = "examProjection", types = { Exam.class }) 
public interface ExamProjection {
    List<QuestionProjection> getQuestionList();

    // Other Getters
}

来源：https://stackoverflow.com/questions/48995744/java-spring-projection-inside-projection