通过java检索neo4j节点数据时出错

通过java检索neo4j节点数据时出错,java,database,graph,neo4j,cypher,Java,Database,Graph,Neo4j,Cypher,我已经通过talend将大约60k个节点加载到neo4j中。我想通过java访问这些节点。Java代码只能获取neo4j本身附带的单个节点,即第0个节点 我的Java代码是: package com.Neo4J; import java.io.File; import java.io.IOException; import java.util.Iterator; import java.util.List; import java.util.Map; import java.util.Map.

我已经通过talend将大约60k个节点加载到neo4j中。我想通过java访问这些节点。Java代码只能获取neo4j本身附带的单个节点,即第0个节点

我的Java代码是:

package com.Neo4J;

import java.io.File;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import javax.naming.spi.DirStateFactory.Result;

import org.neo4j.cypher.javacompat.ExecutionEngine;
import org.neo4j.cypher.javacompat.ExecutionResult;
import org.neo4j.graphdb.GraphDatabaseService;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.Transaction;
import org.neo4j.graphdb.factory.GraphDatabaseFactory;
import org.neo4j.helpers.collection.IteratorUtil;
import org.neo4j.kernel.impl.util.FileUtils;
import org.neo4j.tooling.GlobalGraphOperations;

public class CaseNeo4J {

private static final String DB_PATH = "data/graph.db";
GraphDatabaseService graphDataService;
String nodeResult, resultString, columnsString;
String rows = "";

public static void main(String args[]) {
    CaseNeo4J neoobj = new CaseNeo4J();
    neoobj.connect();

}

void connect() {

    graphDataService = new GraphDatabaseFactory().newEmbeddedDatabase(DB_PATH);
    Transaction transaction = graphDataService.beginTx();

    try {
        ExecutionEngine engine = new ExecutionEngine(graphDataService);
        ExecutionResult result = engine.execute("START n = node(0) return     n");
        System.out.println(result.dumpToString());
    }

    finally {
        transaction.finish();
    }
}
}
正如您在CQL中所看到的,我正在尝试停用节点(0),这将为我提供正确的结果

+-----------+
| n         |
+-----------+
| Node[0]{} |
+-----------+
1 row
但只要我给出类似于START n=node(1)的查询返回n,它就会抛出错误-

Exception in thread "main" org.neo4j.cypher.EntityNotFoundException: Node 1 not found
    at      org.neo4j.cypher.internal.spi.gdsimpl.GDSBackedQueryContext$$anon$1.getById(GDSBackedQueryC     ontext.scala:80)
at   org.neo4j.cypher.internal.spi.gdsimpl.GDSBackedQueryContext$$anon$1.getById(GDSBackedQueryC     ontext.scala:48)
at   org.neo4j.cypher.internal.executionplan.builders.NodeByIdBuilder$$anonfun$org$neo4j$cypher$     internal$executionplan$builders$NodeByIdBuilder$$f$1$1.apply(NodeByIdBuilder.scala:41)
at org.neo4j.cypher.internal.executionplan.builders.NodeByIdBuilder$$anonfun$org$neo4j$cypher$     internal$executionplan$builders$NodeByIdBuilder$$f$1$1.apply(NodeByIdBuilder.scala:41)
at org.neo4j.cypher.internal.executionplan.builders.GetGraphElements$.org$neo4j$cypher$interna     l$executionplan$builders$GetGraphElements$$castElement$1(GetGraphElements.scala:30)
at org.neo4j.cypher.internal.executionplan.builders.GetGraphElements$$anonfun$getElements$3.ap     ply(GetGraphElements.scala:40)
at scala.collection.Iterator$$anon$11.next(Iterator.scala:328)
at scala.collection.Iterator$$anon$11.next(Iterator.scala:328)
at scala.collection.Iterator$$anon$13.next(Iterator.scala:372)
at org.neo4j.cypher.internal.ClosingIterator$$anonfun$next$1.apply(ClosingIterator.scala:44)
at org.neo4j.cypher.internal.ClosingIterator.failIfThrows(ClosingIterator.scala:86)
at org.neo4j.cypher.internal.ClosingIterator.next(ClosingIterator.scala:43)
at scala.collection.Iterator$class.foreach(Iterator.scala:727)
at org.neo4j.cypher.internal.ClosingIterator.foreach(ClosingIterator.scala:31)
at scala.collection.generic.Growable$class.$plus$plus$eq(Growable.scala:48)
at scala.collection.mutable.ListBuffer.$plus$plus$eq(ListBuffer.scala:178)
at scala.collection.mutable.ListBuffer.$plus$plus$eq(ListBuffer.scala:45)
at scala.collection.TraversableOnce$class.to(TraversableOnce.scala:259)
at org.neo4j.cypher.internal.ClosingIterator.to(ClosingIterator.scala:31)
at scala.collection.TraversableOnce$class.toList(TraversableOnce.scala:243)
at org.neo4j.cypher.internal.ClosingIterator.toList(ClosingIterator.scala:31)
at org.neo4j.cypher.PipeExecutionResult.eagerResult(PipeExecutionResult.scala:100)
at org.neo4j.cypher.PipeExecutionResult.dumpToString(PipeExecutionResult.scala:103)
at org.neo4j.cypher.PipeExecutionResult.dumpToString$lzycompute(PipeExecutionResult.scala:143)
at org.neo4j.cypher.PipeExecutionResult.dumpToString(PipeExecutionResult.scala:140)
at org.neo4j.cypher.javacompat.ExecutionResult.dumpToString(ExecutionResult.java:102)
at com.Neo4J.CaseNeo4J.connect(CaseNeo4J.java:45)
at com.Neo4J.CaseNeo4J.main(CaseNeo4J.java:32)
但是,如果我在neo4j shell的web UI中运行START n=node(1)返回n这个查询,它会给出正确的结果


对此有什么想法吗?如果我能在这里找到一些解决方案,我将不胜感激。谢谢

您确定指向的数据位置与neo4j服务器实例和talend使用的DB_路径相同吗?你能检查一下绝对路径吗?AFAIK当您在不存在数据的路径上启动嵌入式数据库实例时,它会从头创建一个空数据集,其中只包含id为0的根节点。

能够解决此问题。提及完整的数据库路径。感谢所有为此付出时间的人