我对neo4j 很陌生。我读过这个问题（Cypher Query not found Node）但它不起作用。我收到错误消息，找不到 auto_node_index。也许是因为我使用的是 BatchInserter？
对于我的实验，我使用 neo4j 1.8.2 和带有嵌入式数据库的编程语言 Java。
我想使用 BatchInserter 和 BatchInserterIndex 将一些数据放入数据库，如http://docs.neo4j.org/chunked/milestone/batchinsert.html中所述。
BatchInserter myInserter = BatchInserters.inserter(DB_PATH);
BatchInserterIndexProvider indexProvider =
new LuceneBatchInserterIndexProvider( myInserter );
BatchInserterIndex persons =
indexProvider.nodeIndex( "persons", MapUtil.stringMap( "type", "exact" ) );
persons.setCacheCapacity( "name", 10000 );
首先，我从 TGF 文件中读取数据，创建节点并将其放入插入器，如下所示：
properties = MapUtil.map("name", actualNodeName, "birthday", birthdayValue);
long node = myInserter.createNode(properties);
nodes.add(node);
persons.flush();
插入工作正常，但是当我想用 Cypher 搜索节点时，结果为空
ExecutionEngine engine = new ExecutionEngine( db );
String query =
"start n=node:persons(name='nameToSearch') "
+ " match n-[:KNOWS]->m "
+ " return n.id, m ";
ExecutionResult result = engine.execute( query );
System.out.println(result);
另一方面，当我使用 Traverser 类并在根节点上开始搜索时，我收到了由名为“nameToSearch”的节点连接的节点。
谁能解释一下，为什么我不能用 Cypher 获得节点！
这是批量插入的完整方法：
public long batchImport() throws IOException{
String actualLine;
ArrayList<Long> nodes = new ArrayList<Long>();
Map<String,Object> properties = new HashMap<String,Object>();
//delete all nodes and edges in the database
FileUtils.deleteRecursively(new File(DB_PATH ));
BatchInserter myInserter = BatchInserters.inserter(DB_PATH);
BatchInserterIndexProvider indexProvider =
new LuceneBatchInserterIndexProvider( myInserter );
BatchInserterIndex persons =
indexProvider.nodeIndex( "persons", MapUtil.stringMap( "type", "exact" ) );
persons.setCacheCapacity( "name", 10000 );
long execTime = 0;
try{
//Get the file which contains the graph informations
FileReader inputFile = new FileReader(UtilFunctions.searchFile(new File(PATH_OUTPUT_MERGED_FILES), "nodesAndEdges").get(0));
LineNumberReader inputLine = new LineNumberReader(inputFile);
// Read nodes up to symbol #
execTime = System.nanoTime();
while ((actualLine=inputLine.readLine()).charAt(0) != '#'){
StringTokenizer myTokenizer = new StringTokenizer(actualLine);
// Read node number
String actualNodeNumber = myTokenizer.nextToken();
// Read node name
String actualNodeName = myTokenizer.nextToken() + " " + myTokenizer.nextToken();
//Read property
myTokenizer.nextToken();
String actualNodePropertyKey = BIRTHDAY_KEY;
String actualNodePropertyValue = myTokenizer.nextToken();
actualNodePropertyValue = actualNodePropertyValue.substring(1, actualNodePropertyValue.length()-1);
// Insert node information
properties = MapUtil.map("name", actualNodeName, "birthday", actualNodePropertyValue, "id", actualNodeNumber);
long node = myInserter.createNode(properties);
nodes.add(node);
persons.flush();
}
// Read edges up to end of file
int countEdges = 0;
while ((actualLine=inputLine.readLine()) != null){
StringTokenizer myTokenizer = new StringTokenizer(actualLine);
// Read start node number
String actualStartNodeNumber = myTokenizer.nextToken();
// Read destination node number
String actualDestinationNodeNumber = myTokenizer.nextToken();
// Read relationship type
String actualRelType = myTokenizer.nextToken();
// Insert node information into ArrayList
int positionStartNode = Integer.parseInt(actualStartNodeNumber);
int positionDestinationNode = Integer.parseInt(actualDestinationNodeNumber);
properties.clear();
if (countEdges == 0) {
myInserter.createRelationship(0, nodes.get(positionStartNode-1), RelType.ROOT, properties);
myInserter.createRelationship(nodes.get(positionStartNode-1), nodes.get(positionDestinationNode-1), RelType.KNOWS, properties);
}
else
{
myInserter.(nodes.get(positionStartNode-1), nodes.get(positionDestinationNode-1), RelType.KNOWS, properties);
}
countEdges++;
}
indexProvider.shutdown();
myInserter.shutdown();
execTime = System.nanoTime() - execTime;
// Close input file
inputLine.close();
inputFile.close();
}
catch (Throwable e){
System.out.println(e.getMessage());
e.printStackTrace();
}
return execTime;
}