0

任何人都可以帮助解决这些 Neo4j (1.9) 错误和使用 JDK 1.6 和 Heroku 的 RestApi。

代码的目的只是演示在 Java 中使用 cypher 和 Neo4j 的功能。我知道只有 RestAPI 在 Heroku 工作。

package com.example;

import java.util.List;

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;
import org.neo4j.helpers.collection.*;
import org.neo4j.rest.graphdb.RestAPI;
import org.neo4j.rest.graphdb.RestAPIFacade;
import org.neo4j.rest.graphdb.RestGraphDatabase;
import org.neo4j.rest.graphdb.query.RestCypherQueryEngine;
import org.neo4j.rest.graphdb.util.*;
import org.springframework.stereotype.Component;
import java.util.Map;


 import com.example.IDatabaseConnector;
//import org.neo4j.rest.graphdb.RestGraphDatabase;
//import org.neo4j.

@Component
//public class Neo4jDatabaseConnector implements IDatabaseConnector {
public class Neo4jDatabaseConnector implements IDatabaseConnector{

    Node aNode;
    Node first;
    Node second;
    Relationship relation;
    private static GraphDatabaseService GraphDb;
    private static RestAPI restAPI;
    Transaction txn;

    private static enum RelTypes implements RelationshipType
    {
        KNOWS,
        USAGE
    }

    public void showNode( )
    {

        // have to add code for cypher
        RestCypherQueryEngine rcqe = new RestCypherQueryEngine(restAPI);
        //Then just execute your cypher statements using rcqe.query().
     // int length=0;
        String countNodes = "START n=node(*) RETURN count(*)";
        String createNodes = "CREATE (n {name: 'Trevor Oakley'})";
         rcqe.query(createNodes, null);


     // QueryResult <Map<String,Object>> result = rcqe.query(countNodes, null);

        //for  (Map<String, Object> row:result){
        //  length++;   
        //}
        //System.out.println("length="+length);


     // rcqe.query(countNodes, Map<String, Object> row:result);
        //  rcqe.query(countNodes, Map<String,Object>:result)
        //  rcqe.
/*   ExecutionEngine engine = new ExecutionEngine(GraphDb);
        int length=-1;
        try{
            ExecutionResult result = engine.execute("start n=node(*) return n");
            if (result == null){
                length = 0;
            } else
            {
                for (@SuppressWarnings("unused")
                    Map<String, Object> row:result){
                        length++;   
                    }
            }
        } catch (NullPointerException e) {
        //  _log.error(e.getMessage(),e);
            length=-2;
        }

         System.out.println("len="+length);
         */

    }

    public Neo4jDatabaseConnector() {
        //GraphDb=new GraphDatabaseFactory().newEmbeddedDatabase(Neo4j_DBPath);
    }
    public int createDBRest()
    {
         restAPI = new RestAPIFacade(System.getenv("NEO4J_URL"), 
                   System.getenv("NEO4J_USERNAME"), 
                   System.getenv("NEO4J_PASSWORD"));
        try{
              GraphDb = new RestGraphDatabase(restAPI);
        }
            catch (Exception e){
                    return 1;
            }

           return 0;
    }
    public int createDB(String dbLoc) {

        System.out.println("db loc ="+dbLoc);
        int error = 0;
try{

        GraphDb=new GraphDatabaseFactory().newEmbeddedDatabase(dbLoc); 
    //GraphDb=new GraphDatabaseFactory().newEmbeddedDatabaseBuilder(dbLoc);
        System.out.println("db loc ="+dbLoc);
        String  stringDB = GraphDb.toString();
        System.out.println("connection  ="+stringDB);
}
catch (Exception e){
    System.out.println("error - ");
    error = 1;
}
    return erro

r;
    }

Problem accessing /hello. Reason:

        Error reading as JSON ''
    Caused by:

    java.lang.RuntimeException: Error reading as JSON ''
        at org.neo4j.rest.graphdb.util.JsonHelper.readJson(JsonHelper.java:57)
        at org.neo4j.rest.graphdb.util.JsonHelper.jsonToSingleValue(JsonHelper.java:62)
        at org.neo4j.rest.graphdb.RequestResult.toEntity(RequestResult.java:114)
        at org.neo4j.rest.graphdb.RequestResult.toMap(RequestResult.java:120)
        at org.neo4j.rest.graphdb.ExecutingRestRequest.toMap(ExecutingRestRequest.java:187)
        at org.neo4j.rest.graphdb.ExecutingRestAPI.query(ExecutingRestAPI.java:475)
        at org.neo4j.rest.graphdb.ExecutingRestAPI.query(ExecutingRestAPI.java:495)
        at org.neo4j.rest.graphdb.RestAPIFacade.query(RestAPIFacade.java:233)
        at org.neo4j.rest.graphdb.query.RestCypherQueryEngine.query(RestCypherQueryEngine.java:50)
        at com.example.Neo4jDatabaseConnector.showNode(Neo4jDatabaseConnector.java:53)
        at com.example.HelloServlet.doGet(HelloServlet.java:22)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
        at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:565)
        at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:479)
        at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:119)
        at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:521)
        at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:227)
        at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1031)
        at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:406)
        at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:186)
        at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:965)
        at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)
        at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:111)
        at org.eclipse.jetty.server.Server.handle(Server.java:349)
        at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:449)
        at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:910)
        at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:634)
        at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:230)
        at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:76)
        at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:609)
        at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:45)
        at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:599)
        at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:534)
        at java.lang.Thread.run(Thread.java:679)
    Caused by: java.io.EOFException: No content to map to Object due to end of input
        at org.codehaus.jackson.map.ObjectMapper._initForReading(ObjectMapper.java:2775)
        at org.codehaus.jackson.map.ObjectMapper._readMapAndClose(ObjectMapper.java:2718)
        at org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:1863)
        at org.neo4j.rest.graphdb.util.JsonHelper.readJson(JsonHelper.java:55)
        ... 34 more
    Caused by:

    java.io.EOFException: No content to map to Object due to end of input
        at org.codehaus.jackson.map.ObjectMapper._initForReading(ObjectMapper.java:2775)
        at org.codehaus.jackson.map.ObjectMapper._readMapAndClose(ObjectMapper.java:2718)
        at org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:1863)
        at org.neo4j.rest.graphdb.util.JsonHelper.readJson(JsonHelper.java:55)
        at org.neo4j.rest.graphdb.util.JsonHelper.jsonToSingleValue(JsonHelper.java:62)
        at org.neo4j.rest.graphdb.RequestResult.toEntity(RequestResult.java:114)
        at org.neo4j.rest.graphdb.RequestResult.toMap(RequestResult.java:120)
        at org.neo4j.rest.graphdb.ExecutingRestRequest.toMap(ExecutingRestRequest.java:187)
        at org.neo4j.rest.graphdb.ExecutingRestAPI.query(ExecutingRestAPI.java:475)
        at org.neo4j.rest.graphdb.ExecutingRestAPI.query(ExecutingRestAPI.java:495)
        at org.neo4j.rest.graphdb.RestAPIFacade.query(RestAPIFacade.java:233)
        at org.neo4j.rest.graphdb.query.RestCypherQueryEngine.query(RestCypherQueryEngine.java:50)
        at com.example.Neo4jDatabaseConnector.showNode(Neo4jDatabaseConnector.java:53)
        at com.example.HelloServlet.doGet(HelloServlet.java:22)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
        at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:565)
        at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:479)
        at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:119)
        at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:521)
        at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:227)
        at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1031)
        at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:406)
        at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:186)
        at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:965)
        at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)
        at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:111)
        at org.eclipse.jetty.server.Server.handle(Server.java:349)
        at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:449)
        at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:910)
        at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:634)
        at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:230)
        at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:76)
        at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:609)
        at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:45)
        at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:599)
        at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:534)
        at java.lang.Thread.run(Thread.java:679)
4

1 回答 1

0

答案是根据即时错误填写用户和密码字段，如下所示。

String neo4jURL = System.getenv("NEO4J_URL");
        String user="user";
        String password="password";

        try{
        URL url = new URL(neo4jURL);
        String userInfo = url.getUserInfo();
        String[] userDetails = userInfo.split(":");
        user = userDetails[0];
        password = userDetails[1];

        } catch (MalformedURLException e) {
        //
        }
于 2013-03-31T16:30:17.180 回答