Question

在我的项目中，我有 MapNodes ，它们通过关系ConnectRelation连接。 ConenctRelation有一个属性长度。节点及其关系会毫无问题地保存到Neo4J数据库中。但是在加载节点时，relationsList为空。

MapNode类

@NodeEntity
public abstract class MapNode extends Circle implements IObservable{

@GraphId
Long id;

@Relationship(type = "CONNECTS_TO")
private ArrayList<ConnectRelation> relations = new ArrayList<>();

@Property(name="x")
private double xCoordinate;

@Property(name="y")
private double yCoordinate;

public ConnectRelation connectToNode(MapNode otherNode){
    ConnectRelation relation = new ConnectRelation(this,otherNode);
    relation.setLength(2);
    this.relations.add(relation);
    return relation;
}
.
.

ConnectRelation类：

@RelationshipEntity
public class ConnectRelation extends Line implements IObserver {

@GraphId
Long id;

@StartNode
MapNode startNode;

@EndNode
MapNode endNode;

@Property(name="startX")
private double startXCoordinate;
@Property(name="startY")
private double startYCoordinate;

@Property(name="endX")
private double endXCoordinate;
@Property(name="endY")
private double endYCoordindate;

@Property(name="length")
private double length;
.
.

填写并加载方法：

 public static void fillDb(){
    getSession().purgeDatabase();

    Room roomOne = new Room();
    roomOne.setXCoordinate(100);
    roomOne.setYCoordinate(100);
    Room roomTwo = new Room();
    roomTwo.setXCoordinate(200);
    roomTwo.setYCoordinate(200);

    ConnectRelation connectRelation = roomOne.connectToNode(roomTwo);

    getSession().save(roomOne);
    getSession().save(roomTwo);
    getSession().save(connectRelation);
}

public void loadNodes(){
    mapNodeList = new ArrayList<>(DatabaseRepository.getSession().loadAll(MapNode.class,2));
    mapNodeList.forEach(n -> {
        n.getRelations().forEach(r -> {
            if(!relationList.contains(r)){
                relationList.add(r);
            }
        });
    });
}

我遇到的问题是，加载节点时MapNode中的关系字段为空，即使深度设置为大于1的值。

提前致谢！

Answer 1

我能看到的唯一显而易见的事情是@RelationshipEntity -

上没有定义关系类型

@RelationshipEntity(type = "CONNECTS_TO")
public class ConnectRelation...

可能就是这样 - 请添加它，如果关系仍未加载，你可以打开调试并分享任何感兴趣的内容吗？添加

<logger name="org.neo4j.ogm" level="debug" />

到logback.xml

Neo4j-OGM关系未被加载

1 个答案: