春天的MongoDB + QueryDSL查詢通過@DBRef相關列表

Question

@Document(collection="users") 
public class User{ 
    @Id 
    private int id; 

    private String name; 
    ... 
    //getters-setters 
} 

@Document(collection="models") 
public class Model{ 
    @Id 
    private int id; 
    private String name; 
    @DBRef 
    private List<User> users; 
    ... 
    //getters-setters 
} 

我試過這個解決方案，但它不返回任何東西：

QMODEL模型=新QMODEL（）; Pageableable page = new PageRequest（0，100）;

return modelsRepository.findAll（model.users.any（）。id.eq（anUserId），pageable）;

Answer 1

我認爲這一切都取決於MongoDB集合中的JSON數據。

在你的情況下，「models」集合應該具有「users」數組的屬性。只要密鑰名稱匹配（即「用戶」），它就可以工作。

詳細示例： -

下面的示例工作正常。

人物合集： -

{ 
    "_id" : ObjectId("57c8269b3ee7df409d4d2b64"), 
    "name" : "Erin", 
    "places" : [ 
     { 
      "$ref" : "places", 
      "$id" : ObjectId("57c813b33ee7df409d4d2b58")     
     } 
    ], 
    "url" : "bc.example.net/Erin" 
} 

地點集合： -

{ 
    "_id" : ObjectId("57c813b33ee7df409d4d2b58"), 
    "name" : "Broadway Center", 
    "url" : "bc.example.net" 
} 

類： -

地方類： -

@Document(collection = "places") 
public class Places implements Serializable { 

    private static final long serialVersionUID = -5500334641079164017L; 

    @Id 
    private String id; 

    private String name; 

    private String url; 

    ...get and setters 
} 

人物類： -

@Document(collection = "people") 
public class People implements Serializable { 

    private static final long serialVersionUID = 6308725499894643034L; 

    @Id 
    private String id; 

    private String name; 

    @DBRef 
    private List<Places> places; 

    private String url; 

    ...get and setters 
} 

庫類： -

@Repository 
public interface PeopleRepository extends PagingAndSortingRepository<People, String> { 

    public People findById(String id); 

    @Query(value = "{ 'status' : ?0 }") 
    public Page<People> findByStatus(String status, Pageable pageable); 

} 

的FindAll： -

public Boolean findAllPeople() { 

     Page<People> peoplePage = peopleRepository.findAll(new PageRequest(0, 20)); 

     System.out.println("Total elements :" + peoplePage.getTotalElements()); 

     for (People people : peoplePage) { 
      System.out.println("People id :" + people.getId()); 
      System.out.println("Place size :" + people.getPlaces().size()); 
      people.getPlaces().forEach(p -> System.out.println(p.getName())); 
     } 

     return true; 

    }