spring - Spring MongoDB + QueryDSL 通过@DBRef 查询相关列表

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
}

我尝试了这个解决方案，但它没有返回任何东西：

QModel 模型 = 新 QModel(); Pageable pageable = new PageRequest(0, 100);

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

Answer 1

我认为这一切都取决于 MongoDB 集合中的 JSON 数据。

在您的情况下，“模型”集合应该具有“用户”数组的属性。只要键名匹配（即“用户”），它就可以工作。

详细示例：-

以下示例工作正常。

人物收藏：-

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

地方集合：-

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

课程：-

地方类： -

@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
}

人物类：-

@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
}

存储库类：-

@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);

}

找到所有：-

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;

    }