尝试通过Gremlin通过REST访问Neo4j数据库进行遍历时出错

Question

I am using Gremlin over Neo4j Database. I'm able to load the tinkergraph database and do gremlin traversal on it, but unable to load local-database and do the traversal on it.

From tinker graph on the console i'm using following commands and it works fine:

g = new TinkerGraph();
g.loadGraphXML('/db/data/graph-example-1.xml');
g.V.name    this works fine and getting the expected results.

Even from Java-code i'm able to do it. I send the same command as:

final String scriptURI = SERVER_ROOT_URI + "ext/GremlinPlugin/graphdb/execute_script";
WebResource resource = Client.create().resource(scriptURI);
String entity = toJsonNameValuePairCollection("script", " g = new TinkerGraph();g.loadGraphXML('/db/data/graph-example-1.xml');g.V.name");
ClientResponse response = resource.accept(MediaType.APPLICATION_JSON).type(MediaType.APPLICATION_JSON).entity(entity .post(ClientResponse.class);

But when I try to access data from hard-disk that I have created at 'db/data/' it's working fine in console but not through the java code.

Console commands:

g = new Neo4jGraph('db/data/'); gVname

I'm getting the expected output.

But through the Java code I'm getting following error: javax.script.ScriptException: java.lang.RuntimeException: java.io.FileNotFoundException

my java code is:

final String scriptURI = SERVER_ROOT_URI + "ext/GremlinPlugin/graphdb/execute_script"; WebResource resource = Client.create().resource(scriptURI); String entity = toJsonNameValuePairCollection("script", "g = new Neo4jGraph('db/data/');gVname"); ClientResponse response = resource.accept(MediaType.APPLICATION_JSON).type(MediaType.APPLICATION_JSON).entity(entity .post(ClientResponse.class);

Answer 1

in Neo4j Server, g is already bound to the server Neo4j graph instance, so you can directly use it (omit the g = new Neo4jGraph() in the REST call to the Gremlin plugin).

Finally, if you really need to open a new database, make sure the 'db/data/' in the script is pointing where you want it. It is a relative path and thus relative to the servers working dir. Maybe you can do first

dir = new File('db/data') dir.getAbsolutePath()

and return that?