在Spring Data Neo4j中查询关系

Question

我正在设计一个信标网络，其中信标彼此相邻，使用Neo4j数据库，其中有一个实体和一个关系类。我需要检索两个信标之间的关系，但不知道如何检索。下面是两个类

Beacon类

public class Beacon {
    @Id
    private String MAC;
    private String description;
    private String location;

    @Relationship(type = "ADJACENT")
    private List<Adjacent> adjacentList = new ArrayList<>();

    public Beacon() {
    }

    public Beacon(String MAC, String description, String location) {
        this.MAC = MAC;
        this.description = description;
        this.location = location;
    }


    public void addAdjacency(Adjacent adjacent){
        if (this.adjacentList==null){
            this.adjacentList=new ArrayList<>();
        }
        this.adjacentList.add(adjacent);
    }

//Getters and Setters are excluded

}

相邻关系类

public class Adjacent {
    @Id
    @GeneratedValue
    private Long id;

    private int angle;
    private int cost;

    @StartNode
    private Beacon startBeacon;

    @EndNode
    private Beacon endBeacon;

    public Adjacent() {
    }

    public Adjacent(int angle, int cost, Beacon startBeacon, Beacon endBeacon) {
        this.angle = angle;
        this.cost = cost;
        this.startBeacon = startBeacon;
        this.endBeacon = endBeacon;
    }
//Getters and Setters are excluded

}

我已经尝试创建存储库和检索，但是即使查询在Neo4j浏览器中工作，它在这里也不检索任何数据，只检索空白括号。

public interface AdjacentRepository extends Neo4jRepository<Adjacent,Long> 
{
@Query("match (b:Beacon{MAC:\"f:f:f:f\"})-[a:ADJACENT]-(c:Beacon{MAC:\"r:r:r:r\") return a")
    Adjacent findaRelationshipp();
}

任何帮助都是非常感谢的。

Answer 1

您需要使用return *或return a, b, c，这样OGM才能推断出将查询响应映射到对象模型所需的所有细节。

查询在Neo4j浏览器中工作的原因是它会自动修改查询以展开相邻路径，在本例中为信标对象。