Question

我正在尝试使用“Hello World＆＃39;对于Neo4j。问题是，当我启动服务器并检查neo4j的浏览器（localhost：7474）时，我看不到任何节点的图形可视化。

import java.io.File;

import org.neo4j.graphdb.Direction;
import org.neo4j.graphdb.GraphDatabaseService;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.Relationship;
import org.neo4j.graphdb.RelationshipType;
import org.neo4j.graphdb.Transaction;
import org.neo4j.graphdb.factory.GraphDatabaseFactory;

public class MyFirstMain
{
    private static final String DB_PATH = "/neo4j/data/graph.db";

    public String greeting;

    // START SNIPPET: vars
    GraphDatabaseService graphDb;
    Node firstNode;
    Node secondNode;
    Relationship relationship;
    // END SNIPPET: vars

    // START SNIPPET: createReltype
    private static enum RelTypes implements RelationshipType
    {
        KNOWS
    }
    // END SNIPPET: createReltype

    public static void main( final String[] args )
    {
        MyFirstMain hello = new MyFirstMain();
        hello.createDb();
//        hello.removeData();
//        hello.shutDown();
    }

    void createDb()
    {
         // START SNIPPET: startDb
        graphDb = new GraphDatabaseFactory().newEmbeddedDatabase( DB_PATH );
        registerShutdownHook( graphDb );
        // END SNIPPET: startDb

        // START SNIPPET: transaction
        try ( Transaction tx = graphDb.beginTx() )
        {
            // Database operations go here
            // END SNIPPET: transaction
            // START SNIPPET: addData
            firstNode = graphDb.createNode();
            firstNode.setProperty( "message", "Hello, " );
            secondNode = graphDb.createNode();
            secondNode.setProperty( "message", "World!" );

            relationship = firstNode.createRelationshipTo( secondNode, RelTypes.KNOWS );
            relationship.setProperty( "message", "brave Neo4j " );
            // END SNIPPET: addData

            // START SNIPPET: readData
            System.out.print( firstNode.getProperty( "message" ) );
            System.out.print( relationship.getProperty( "message" ) );
            System.out.print( secondNode.getProperty( "message" ) );
            // END SNIPPET: readData

            greeting = ( (String) firstNode.getProperty( "message" ) )
                    + ( (String) relationship.getProperty( "message" ) )
                    + ( (String) secondNode.getProperty( "message" ) );

            // START SNIPPET: transaction
            tx.success();
        }
        // END SNIPPET: transaction
    }

     // START SNIPPET: shutdownHook
    private static void registerShutdownHook( final GraphDatabaseService graphDb )
    {
        // Registers a shutdown hook for the Neo4j instance so that it
        // shuts down nicely when the VM exits (even if you "Ctrl-C" the
        // running application).
        Runtime.getRuntime().addShutdownHook( new Thread()
        {
            @Override
            public void run()
            {
                graphDb.shutdown();
            }
        } );
    }
    // END SNIPPET: shutdownHook
}

我不想使用其他任何东西，除了neo4j内置的浏览器。我该怎么办？

提前致谢。

Answer 1

必须关闭服务器，然后创建数据，然后再次启动服务器，不能同时使用两个数据库进程中的相同数据目录。

你的DB_PATH也错了，你不能在那里有一颗星。

Neo4j - 浏览器可视化错误

1 个答案: