问题
I am trying to initialize an in-memory graph using TinkerGraph.
Firstly, i have defined the bean in my context xml file and tried to initialise the TinkerGraph.
My intention is to unit test the classes that i have created for forming the gremlin queries, the end queries that i get from these classes are in the form of a string, so in order to execute them through the TinkerGraph, i have the used the approach given in the following post: Get Gremlin query as a String and execute it in java without submitting it to the GremlinServer
I would also like to know whether the approach that i have taken is the preferred approach, for running the gremlin queries as part of the unit testing?
Following are the dependencies i have included in the pom.xml:
<dependency>
<groupId>org.apache.tinkerpop</groupId>
<artifactId>tinkergraph-gremlin</artifactId>
<version>3.2.4</version>
</dependency>
<dependency>
<groupId>org.apache.tinkerpop</groupId>
<artifactId>gremlin-groovy</artifactId>
<version>3.0.2-incubating</version>
</dependency>
EmbeddedGremlinQueryEngine is as follows:
import org.apache.tinkerpop.gremlin.driver.Result;
import org.apache.tinkerpop.gremlin.driver.ResultSet;
import org.apache.tinkerpop.gremlin.groovy.jsr223.GremlinGroovyScriptEngine;
import org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.GraphTraversalSource;
import org.apache.tinkerpop.gremlin.structure.Graph;
import org.apache.tinkerpop.gremlin.tinkergraph.structure.TinkerGraph;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.script.Bindings;
import javax.script.ScriptEngine;
import javax.script.ScriptException;
import java.util.List;
public class UcsEmbeddedGremlinQueryEngine implements GremlinEngine{
private static final Logger logger = LoggerFactory.getLogger(UcsEmbeddedGremlinQueryEngine.class);
private GraphTraversalSource graphTraversalSource = null;
private Graph graph = null;
private ScriptEngine engine = null;
private Bindings bindings = null;
public UcsEmbeddedGremlinQueryEngine() {
graph = TinkerGraph.open();
graphTraversalSource = graph.traversal();
engine = new GremlinGroovyScriptEngine();
bindings = engine.createBindings();
bindings.put("g", graphTraversalSource);
}
public void shutdown() throws Exception {
if (graph != null){
graph.close();
}
logger.info("TinkerGraph shutdown complete.");
}
@Override
public List<Result> query(String query) {
List<Result> res = null;
try {
ResultSet results = (ResultSet) engine.eval(query, bindings);
res = results.all().join();
for (Result r : res) {
System.out.println("result: " + r + '\n');
}
} catch (ScriptException e) {
e.printStackTrace();
}
return res;
}
// This function reads the initScript and run them as gremlin queries.
public synchronized void initialize() {
logger.debug("Initializing embedded TinkerGraph. This will only take a few seconds....");
//TODO include the execution of queries as part of initialisation
}
}
Stack trace is as follows:
java.lang.NoClassDefFoundError: org/apache/tinkerpop/gremlin/process/traversal/dsl/graph/GraphTraversalSource$GraphTraversalSourceStub
at org.apache.tinkerpop.gremlin.groovy.loaders.StepLoader.load(StepLoader.groovy:54)
at org.codehaus.groovy.vmplugin.v7.IndyInterface.selectMethod(IndyInterface.java:236)
at org.apache.tinkerpop.gremlin.groovy.loaders.GremlinLoader.load(GremlinLoader.groovy:28)
at org.apache.tinkerpop.gremlin.groovy.jsr223.GremlinGroovyScriptEngine.<init>(GremlinGroovyScriptEngine.java:189)
at org.apache.tinkerpop.gremlin.groovy.jsr223.GremlinGroovyScriptEngine.<init>(GremlinGroovyScriptEngine.java:172)
at com.intuit.gro.mcsdata.gemlinengine.UcsEmbeddedGremlinQueryEngine.<init>(UcsEmbeddedGremlinQueryEngine.java:28)
EmbeddedGremlinQueryEngine is defined as a bean in the xml file, when the bean is loaded i get the error as Constructor threw exception; nested exception is java.lang.NoClassDefFoundError: org/apache/tinkerpop/gremlin/process/traversal/dsl/graph/GraphTraversalSource$GraphTraversalSourceStub
I don't understand how the GraphTraversalSourceStub comes into picture during initialization, I was not able to find any information about it. Any help would be appreciated.
回答1:
I think your problem is that you're:
- using really really old versions of TinkerPop
- the old versions you're using are probably incompatible
I'm not sure if you have a reason for using 3.2.4, but if so, make sure gremlin-groovy is also 3.2.4. Note that the 3.2.x line of code is largely not maintained at this point with the last release being 3.2.11 about 6 months ago. If you are developing a new application then I highly recommend that you simply utilize the latest version of 3.4.2 which released a few weeks ago.
As for your testing approach, I suppose that's fine. If you have test Gremlin strings then you really don't have much other choice in the matter, short of using Gremlin Server. Obviously providing a test harness for GremlinGroovyScriptEngine is a lot easier to do.
回答2:
For version 3.4.0 you need at least the following classpath.
set cp=%cp%;C:\pathToM2Repo\org\apache\tinkerpop\gremlin-core\3.4.0\gremlin-core-3.4.0.jar
set cp=%cp%;C:\pathToM2Repo\org\apache\tinkerpop\gremlin-driver\3.4.0\gremlin-driver-3.4.0.jar
set cp=%cp%;C:\pathToM2Repo\org\apache\tinkerpop\gremlin-groovy\3.4.0\gremlin-groovy-3.4.0.jar
set cp=%cp%;C:\pathToM2Repo\org\apache\tinkerpop\gremlin-server\3.4.0\gremlin-server-3.4.0.jar
set cp=%cp%;C:\pathToM2Repo\org\apache\tinkerpop\gremlin-shaded\3.4.0\gremlin-shaded-3.4.0.jar
set cp=%cp%;C:\pathToM2Repo\org\apache\tinkerpop\tinkergraph-gremlin\3.4.0\tinkergraph-gremlin-3.4.0.jar
set cp=%cp%;C:\pathToM2Repo\org\apache\tinkerpop\tinkerpop\3.4.0\tinkerpop-3.4.0.jar
set cp=%cp%;C:\pathToM2Repo\commons-configuration\commons-configuration\1.10\commons-configuration-1.10.jar
set cp=%cp%;C:\pathToM2Repo\org\slf4j\slf4j-api\1.7.25\slf4j-api-1.7.25.jar
set cp=%cp%;C:\pathToM2Repo\org\apache\logging\log4j\log4j-slf4j-impl\2.11.1\log4j-slf4j-impl-2.11.1.jar
set cp=%cp%;C:\pathToM2Repo\org\apache\logging\log4j\log4j-api\2.11.1\log4j-api-2.11.1.jar
set cp=%cp%;C:\pathToM2Repo\org\apache\logging\log4j\log4j-core\2.11.1\log4j-core-2.11.1.jar
set cp=%cp%;C:\pathToM2Repo\org\codehaus\groovy\groovy\2.5.4\groovy-2.5.4-indy.jar
set cp=%cp%;C:\pathToM2Repo\org\codehaus\groovy\groovy-json\2.5.4\groovy-json-2.5.4-indy.jar
set cp=%cp%;C:\pathToM2Repo\org\codehaus\groovy\groovy-xml\2.5.5\groovy-xml-2.5.5.jar
set cp=%cp%;C:\pathToM2Repo\org\codehaus\groovy\groovy-templates\2.5.5\groovy-templates-2.5.5.jar
set cp=%cp%;C:\pathToM2Repo\org\javatuples\javatuples\1.2\javatuples-1.2.jar
set cp=%cp%;C:\pathToM2Repo\commons-collections\commons-collections\3.2.2\commons-collections-3.2.2.jar
set cp=%cp%;C:\pathToM2Repo\io\netty\netty-all\4.1.31.Final\netty-all-4.1.31.Final.jar
来源：https://stackoverflow.com/questions/56524089/how-to-fix-java-lang-noclassdeffounderror-org-apache-tinkerpop-gremlin-process