Spring Repository Projection 获取一个对象的子对象

Question

我经常使用 Spring Repository 接口。一个对我来说工作得很好，但后来我意识到我需要更多一点。我想再上一层 get()

我在 Intranet 上工作，因此无法复制和粘贴，但希望以下内容能够提供足够的信息以使其易于理解...

@Entity
@Table(name="person")
class Person {
  ...
}

@Entity
@Table(name="requisite")
class Requisite {
  ...
  @OneToOne
  @JoinColumn
  private Document document;
}

@Entity
@Table(name="person_requisite")
class PersonRequisite {
  ...
  @ManyToOne
  @JoinColumn(name="person_id") 
  private Person person;
  ...
  @ManyToOne
  @JoinColumn(name="requisite_id") 
  private Requisite requisite;
  ...
}

@Projection(name="personRequisiteProjection", types={PersonRequisite.class})
public interface PersonRequisiteProjection {
  ...
  Person getPerson();
  Requisite getRequisite();
  ...
}

这是我现在得到的表示......

"personRequisites" : [ {
   ...
   "requisite" : {
     id : 1,
     ...
     no document object or document id from the requisite
    },
   "person" : {
     id : 33,
     ...
   },
   ...
 ]
...

这是我想要的表示......

"personRequisites" : [ {
   ...
   "requisite" : {
     id : 1,
     ...
     "document" : {
       "id" : 55,
       "name" : blah,
       ...
     }
    },
   "person" : {
     id : 33,
     ...
   },
   ...
 ]
...

我知道这是不正确的，但我基本上想要

@Projection(name="personRequisiteProjection", types={PersonRequisite.class})
public interface PersonRequisiteProjection {
  ...
  //i know, this would be out of place if it worked but trying to emphasize what i want...
  Document getRequisite().getDocument();
  //i'd still want Requisite getRequisite() as well but you get what i am after
  ...

  //or more appropriately, force document to show up in Requisite here...
  Requisite getRequisite();  
  ...
}

Answer 1

@Projection(name="personRequisiteProjection", types={PersonRequisite.class})
public interface PersonRequisiteProjection {
    ...
  @Value("#{target.requisite.document}")
  Document getRequisite().getDocument();
  //i'd still want Requisite getRequisite() as well but you get what i  am after
  ...

  //or more appropriately, force document to show up in Requisite   here...
  Requisite getRequisite();  
  ...
}