如何使用 java 插件在 Neo4j 中 return 节点邻居？

Question

在 Cypher 中返回的邻居看起来像这样：

START n=node({nodeId}) MATCH n--m RETURN m;

我努力创建一个具有相同功能的 Java 插件。之后我想看看返回的邻居的属性等等。这是我尝试获取关系及其端节点的代码。我究竟做错了什么？我只返回节点本身，但没有返回 "while-Loop".

import java.util.Iterator;
import java.util.stream.Stream;
import org.neo4j.graphdb.GraphDatabaseService;
import org.neo4j.graphdb.Label;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.Relationship;
import org.neo4j.graphdb.ResourceIterator;
import org.neo4j.logging.Log;
import org.neo4j.procedure.*;
import org.neo4j.procedure.Description;
import org.neo4j.procedure.Name;

public class Correlation {

@Context
public GraphDatabaseService db;

@Context
public Log log;


@UserFunction(value = "boris.getNeighbours")
@Description("boris.getNeighbours- finds Nodes one step away")
public Node passName2(@Name("nodeId") long nodeId)

{

    Node node = db.getNodeById( nodeId );
    Iterable<Relationship> rels = node.getRelationships();
    Iterator<Relationship> I_rel =  rels.iterator();

    while (I_rel.hasNext()) {
        Relationship rel = I_rel.next();
        Node endNode = rel.getEndNode();
        return endNode;
    }
return node;
}
}

Answer 1

这个有效：

public class NodeFinder {

@Context
public GraphDatabaseService db;

@Context
public Log log;

@Procedure 
@Description("finds Nodes one step away")
public Stream<NodeResult> passName2(@Name("nodeId") long nodeId)

{

    Node node = db.getNodeById(nodeId);
    Iterable<Relationship> rels = node.getRelationships();
    Stream<Relationship> relsStream = StreamSupport.stream(rels.spliterator(), false);
    Stream<NodeResult> myNodes = relsStream.map(r -> new NodeResult(r));  

    return myNodes;

}


public class NodeResult 
{
    //What i return
    public Node node;

     //Constructor
     public NodeResult(Relationship item) 
     {            
        this.node = item.getEndNode();
     }

}
}

如何使用 java 插件在 Neo4j 中 return 节点邻居？

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