Ich habe 2 Knoten: Name und Stadt. und eine Beziehung zwischen diesen beiden ist (Name) [: LIVES_IN] -> (Stadt). Ich versuche, eine Abfrage zu generieren, um herauszufinden, wer die in Stadt X lebenden Personen sind (wobei X aus einem Textfeld stammt).

Ich versuche dieses Konstrukt dieser Abfrage gemäß dem Vorschlag von Luanne und Micheal Hunger:

import java.io.IOException;
import java.util.ArrayList;
import org.neo4j.graphdb.GraphDatabaseService;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.RelationshipType;
import org.neo4j.graphdb.Transaction;
import org.neo4j.graphdb.factory.GraphDatabaseFactory;
import org.neo4j.helpers.collection.IteratorUtil;
import org.neo4j.cypher.javacompat.ExecutionEngine;
import org.neo4j.cypher.javacompat.ExecutionResult;

public class registrationFrame extends javax.swing.JFrame {

    public static final String DB_PATH = "D://data";
    public static GraphDatabaseService graphDb = null;
    Node person;
    Node password;
    Node city;
    String nodeResulta;

    public registrationFrame() {
        initComponents();
    }
    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {//node and relationship creation code                                         

        try (Transaction tx = graphDb.beginTx();) {
            person = graphDb.createNode();
            person.setProperty("name", jTextField1.getText());
            person.setProperty("password", jPasswordField1.getPassword());
            graphDb.index().forNodes("name").add(person, "name", jTextField1.getText());


            city = graphDb.createNode();
            city.setProperty("city_name", jTextField2.getText());
            graphDb.index().forNodes("city_name").add(city, "city_name", jTextField2.getText());

            person.createRelationshipTo(city, RelTypes.LIVES_IN);

            tx.success();
        }

    }                                        
private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {//query code                                         
        ExecutionEngine engine = new ExecutionEngine(graphDb);
    ExecutionResult result;
    String temp=jTextField2.getText();
    Map<String,Object> params=new HashMap<>();
    //result = engine.execute("START n=node(*) MATCH (x:city)<-[:LIVES_IN]-(y:person) where x.name='"+jTextField2.getText()+"' RETURN y.name;");
    //List<String> columns = result.columns();
    //Iterator<Node> n_column = result.columnAs( "person" );
    try (Transaction ignored = graphDb.beginTx()) {
        //result = engine.execute("START n=node(*) MATCH (x:city)<-[:LIVES_IN]-(y:person) where x.name='"+temp+"' RETURN y");
        // END SNIPPET: execute
        // START SNIPPET: items
        //result = engine.execute("START n=node(*) MATCH (x:city) RETURN x");//this query also returns nothing

        params.put("c_name",temp);
        result=engine.execute("MATCH (city_name:city {city_name:{c_name}})<-[:LIVES_IN]-(person) RETURN person",params);
        System.out.println(result);
        Iterator<Node> n_column = result.columnAs("person");

        for (Node node : IteratorUtil.asIterable(n_column)) {
            // note: we're grabbing the name property from the node,
            // not from the n.name in this case.
            nodeResulta = node + ": " + node.getProperty("name")  + '\n';
            //nodeResult1.add(node.getProperty( "name" ).toString());
        }
        // END SNIPPET: items
    }

        jTextArea1.setText(nodeResulta);// output will show here

    }                       

public static void main(String args[]) {

       java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new registrationFrame().setVisible(true);
                graphDb = new GraphDatabaseFactory().newEmbeddedDatabase(DB_PATH);
                registerShutdownHook(graphDb);
                //System.out.println("Created Social Graph!!");
            }
        });
    }
private static void registerShutdownHook(final GraphDatabaseService graphDb) {
        Runtime.getRuntime().addShutdownHook(new Thread() {
            @Override
            public void run() {
                graphDb.shutdown();
            }
        });
    }

    public static enum RelTypes implements RelationshipType {

        LIVES_IN,
        FRIEND,
        CUISINE,
        LIKES,
        IN
    }

Diese Abfrage liefert jedoch weder ein Ergebnis noch eine Ausnahme.

Ist meine Abfrage richtig? Kann mir jemand sagen, wie ich das beheben kann? Soll ich meine neo4j Version ändern, weil ich alles verfolge, wie Luanne und Miheal HUnger gefragt haben?

Dankeschön