2

以下代码生成以下奇怪的异常：

package com.bmt.contain.spatial.test;

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.Relationship;
import org.neo4j.graphdb.ResourceIterator;
import org.neo4j.graphdb.Transaction;
import org.neo4j.graphdb.factory.GraphDatabaseFactory;
import org.neo4j.graphdb.factory.GraphDatabaseSettings;
import org.neo4j.graphdb.index.Index;
import org.neo4j.gis.spatial.indexprovider.SpatialIndexProvider;

import com.vividsolutions.jts.geom.Coordinate;

public class SpatialTest {

/**
 * @param args
 */
public static void main(String[] args){

    GraphDatabaseService graphDB = new GraphDatabaseFactory()
    .newEmbeddedDatabaseBuilder("var/geo")
    .setConfig(GraphDatabaseSettings.allow_store_upgrade, "true")
    .newGraphDatabase();
    Index<Node> index = null;
    try (Transaction tx = graphDB.beginTx()){
        index = createSpatialIndex(graphDB, "Coordinates");
        tx.success();
    }

    Node ship = null;
    try (Transaction tx = graphDB.beginTx();) {
        ship = graphDB.createNode(MyLabels.Ship);
        ship.setProperty("Name", new String("Phils Powerboat"));
        tx.success();
    }

    routeGenerator(graphDB, ship, index);

    try (Transaction tx = graphDB.beginTx()){
        ExecutionEngine engine = new ExecutionEngine(graphDB);
        ExecutionResult result = engine.execute("START n=node:Coordinates('withinDistance:[100, 9.3, 8.2]') RETURN n");
        System.out.println(result.dumpToString());
    }

    try (Transaction tx = graphDB.beginTx();) {
        ExecutionEngine engine = new ExecutionEngine(graphDB);
        ExecutionResult result = engine.execute("MATCH (n) \n RETURN n");
        System.out.println(result.dumpToString());
        tx.success();
    }

    graphDB.shutdown();
}

/**
 * This returns a new index unless an index with this name already exists, in which case it is returned.
 * @param graphDb
 * @param indexName
 * @return
 */
private static Index<Node> createSpatialIndex(GraphDatabaseService graphDb, String indexName) {
    return graphDb.index().forNodes(indexName, SpatialIndexProvider.SIMPLE_WKT_CONFIG);
}

private static void routeGenerator(GraphDatabaseService graphDb, Node startNode, Index<Node> index){
    try (Transaction tx = graphDb.beginTx();) {
        Coordinate start = new Coordinate(Math.random() * 10,
                Math.random() * 10);
        for (int i = 0; i < 20; i++) {
            Node locationNode = graphDb.createNode(MyLabels.Location);
            locationNode.setProperty("wkt", String.format("POINT(%s %s)", start.x, start.y));   
            Relationship rel = startNode.createRelationshipTo(locationNode, RelTypes.hasLocation);
            start = new Coordinate((start.x + 0.1), start.x + Math.random()* 0.2);
        }

        tx.success();

    }
}
}

该测试应该创建一条随机路线并返回距离起点一定距离内的节点。然而，线条

ExecutionResult result = engine.execute("START n=node:Coordinates('withinDistance:[100, 9.3, 8.2]') RETURN n");
System.out.println(result.dumpToString());

生成错误：“线程“main”中的异常 java.lang.ClassCastException：java.lang.Long 不能转换为 java.lang.Double” - 我已经通过注释掉 System.out 行意味着它来检查这一点运行得很好。

请注意，我在运行之前清理了目录，因此目录中应该没有其他节点。完整的堆栈跟踪如下

Exception in thread "main" java.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.Double
at org.neo4j.gis.spatial.indexprovider.LayerNodeIndex.query(LayerNodeIndex.java:228)
at org.neo4j.gis.spatial.indexprovider.LayerNodeIndex.query(LayerNodeIndex.java:290)
at org.neo4j.cypher.internal.spi.v2_0.TransactionBoundQueryContext$NodeOperations.indexQuery(TransactionBoundQueryContext.scala:169)
at org.neo4j.cypher.internal.compiler.v2_0.spi.DelegatingOperations.indexQuery(DelegatingQueryContext.scala:116)
at org.neo4j.cypher.internal.compiler.v2_0.spi.ExceptionTranslatingQueryContext$ExceptionTranslatingOperations.org$neo4j$cypher$internal$compiler$v2_0$spi$ExceptionTranslatingQueryContext$ExceptionTranslatingOperations$$super$indexQuery(ExceptionTranslatingQueryContext.scala:142)
at org.neo4j.cypher.internal.compiler.v2_0.spi.ExceptionTranslatingQueryContext$ExceptionTranslatingOperations$$anonfun$indexQuery$1.apply(ExceptionTranslatingQueryContext.scala:142)
at org.neo4j.cypher.internal.compiler.v2_0.spi.ExceptionTranslatingQueryContext$ExceptionTranslatingOperations$$anonfun$indexQuery$1.apply(ExceptionTranslatingQueryContext.scala:142)
at org.neo4j.cypher.internal.compiler.v2_0.spi.ExceptionTranslatingQueryContext.org$neo4j$cypher$internal$compiler$v2_0$spi$ExceptionTranslatingQueryContext$$translateException(ExceptionTranslatingQueryContext.scala:149)
at org.neo4j.cypher.internal.compiler.v2_0.spi.ExceptionTranslatingQueryContext$ExceptionTranslatingOperations.indexQuery(ExceptionTranslatingQueryContext.scala:142)
at org.neo4j.cypher.internal.compiler.v2_0.spi.DelegatingOperations.indexQuery(DelegatingQueryContext.scala:116)
at org.neo4j.cypher.internal.compiler.v2_0.executionplan.builders.EntityProducerFactory$$anonfun$2$$anonfun$applyOrElse$2.apply(EntityProducerFactory.scala:66)
at org.neo4j.cypher.internal.compiler.v2_0.executionplan.builders.EntityProducerFactory$$anonfun$2$$anonfun$applyOrElse$2.apply(EntityProducerFactory.scala:64)
at org.neo4j.cypher.internal.compiler.v2_0.executionplan.builders.EntityProducerFactory$$anon$1.apply(EntityProducerFactory.scala:35)
at org.neo4j.cypher.internal.compiler.v2_0.executionplan.builders.EntityProducerFactory$$anon$1.apply(EntityProducerFactory.scala:34)
at org.neo4j.cypher.internal.compiler.v2_0.pipes.StartPipe$$anonfun$internalCreateResults$1.apply(StartPipe.scala:34)
at org.neo4j.cypher.internal.compiler.v2_0.pipes.StartPipe$$anonfun$internalCreateResults$1.apply(StartPipe.scala:33)
at scala.collection.Iterator$$anon$13.hasNext(Iterator.scala:371)
at org.neo4j.cypher.internal.compiler.v2_0.ClosingIterator$$anonfun$hasNext$1.apply$mcZ$sp(ClosingIterator.scala:35)
at org.neo4j.cypher.internal.compiler.v2_0.ClosingIterator$$anonfun$hasNext$1.apply(ClosingIterator.scala:34)
at org.neo4j.cypher.internal.compiler.v2_0.ClosingIterator$$anonfun$hasNext$1.apply(ClosingIterator.scala:34)
at org.neo4j.cypher.internal.compiler.v2_0.ClosingIterator.failIfThrows(ClosingIterator.scala:89)
at org.neo4j.cypher.internal.compiler.v2_0.ClosingIterator.hasNext(ClosingIterator.scala:34)
at scala.collection.Iterator$class.foreach(Iterator.scala:727)
at org.neo4j.cypher.internal.compiler.v2_0.ClosingIterator.foreach(ClosingIterator.scala:30)
at scala.collection.generic.Growable$class.$plus$plus$eq(Growable.scala:48)
at scala.collection.mutable.ListBuffer.$plus$plus$eq(ListBuffer.scala:176)
at scala.collection.mutable.ListBuffer.$plus$plus$eq(ListBuffer.scala:45)
at scala.collection.TraversableOnce$class.to(TraversableOnce.scala:273)
at org.neo4j.cypher.internal.compiler.v2_0.ClosingIterator.to(ClosingIterator.scala:30)
at scala.collection.TraversableOnce$class.toList(TraversableOnce.scala:257)
at org.neo4j.cypher.internal.compiler.v2_0.ClosingIterator.toList(ClosingIterator.scala:30)
at org.neo4j.cypher.internal.compiler.v2_0.PipeExecutionResult.eagerResult(PipeExecutionResult.scala:101)
at org.neo4j.cypher.internal.compiler.v2_0.PipeExecutionResult.dumpToString(PipeExecutionResult.scala:107)
at org.neo4j.cypher.internal.compiler.v2_0.PipeExecutionResult.dumpToString$lzycompute(PipeExecutionResult.scala:152)
at org.neo4j.cypher.internal.compiler.v2_0.PipeExecutionResult.dumpToString(PipeExecutionResult.scala:149)
at org.neo4j.cypher.javacompat.ExecutionResult.dumpToString(ExecutionResult.java:102)
at com.bmt.contain.spatial.test.Initialise.main(Initialise.java:46)
4

1 回答 1

1

解决方案 1 {如果你只想要节点的字符串表示}

ExecutionResult result = engine.execute("START n=node:Coordinates('withinDistance:[100, 9.3, 8.2]') RETURN str(n)");
System.out.println(result.dumpToString());

解决方案 2 {如果您希望遍历节点及其属性}

ResourceIterator<Node> resultIterator;
ExecutionResult result = engine.execute("START n=node:Coordinates('withinDistance:[100, 9.3, 8.2]') RETURN n");
resultIterator = result.columnAs("n");
while(resultIterator.hasNext()){
   System.out.println(resultIterator.next());
}
resultIterator.close();

如果上述两个查询失败，那么您可能想尝试评论中的建议

于 2014-07-08T09:06:34.297 回答