How can I access neo4j running on ( any http or localhost) from android

送分小仙女□ 提交于 2019-12-13 05:09:15

问题


I am successfully implemented neo4j on both mac and java application but I cannot access the same from and android and the it crashes at dbpath.But it keeps crashing.How can I get it to work?

INstead of

graphDb = new EmbeddedGraphDatabase(DB_PATH);

it is

 RestAPI graphDb = new RestAPIFacade("http://localhost:7474/db/data");  

also tried

 GraphDatabaseService graphDb=new RestGraphDatabase(“http://localhost:7474/db/data”);  

Entire Code:

import java.io.File;
import java.io.IOException;

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.kernel.EmbeddedGraphDatabase;
import org.neo4j.kernel.impl.util.FileUtils;

public class EmbeddedNeo4j {
    private static final String DB_PATH = "/home/User/Documents/neo4j/";
    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) {
        EmbeddedNeo4j hello = new EmbeddedNeo4j();
        hello.createDb();
        hello.removeData();
        hello.shutDown();
    }

    void createDb() {
        clearDb();
        // START SNIPPET: startDb
        graphDb = new EmbeddedGraphDatabase(DB_PATH);
        registerShutdownHook(graphDb);
        // END SNIPPET: startDb

        // START SNIPPET: transaction
        Transaction tx = graphDb.beginTx();
        try {
            // Mutating 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();
        } finally {
            tx.finish();
        }
        // END SNIPPET: transaction
    }

    private void clearDb() {
        try {
            FileUtils.deleteRecursively(new File(DB_PATH));
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    void removeData() {
        Transaction tx = graphDb.beginTx();
        try {
            // START SNIPPET: removingData
            // let's remove the data
            firstNode.getSingleRelationship(RelTypes.KNOWS, Direction.OUTGOING)
                    .delete();
            firstNode.delete();
            secondNode.delete();
            // END SNIPPET: removingData

            tx.success();
        } finally {
            tx.finish();
        }
    }

    void shutDown() {
        System.out.println();
        System.out.println("Shutting down database ...");
        // START SNIPPET: shutdownServer
        graphDb.shutdown();
        // END SNIPPET: shutdownServer
    }

    // 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 example before it's completed)
        Runtime.getRuntime().addShutdownHook(new Thread() {
            @Override
            public void run() {
                graphDb.shutdown();
            }
        });
    }
    // END SNIPPET: shutdownHook

}

回答1:


EmbeddedGraphDatabase can only be used if the DB and your client code should reside in the same JVM (therefore the word 'embedded').

If you want to remote access a Neo4j server the best ways today is either communicating with the transactional Cypher endpoint directly or using the Neo4j JDBC driver. Please note, in both cases you use Cypher to interact with the graph.

The library for java rest bindings is originated in the days where the two mentioned approached where not yet in place - so java-rest-bindings will be deprecated in the future.



来源:https://stackoverflow.com/questions/28539896/how-can-i-access-neo4j-running-on-any-http-or-localhost-from-android

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