通过Java连接Titan db-引发异常

Question

I have a java code snippet

 TitanGraph g = TitanFactory.open("titan-all-0.4.4/conf/titan-berkeleydb.properties"); 

where titan-berkeleydb .properties is the in build config file that comes with Titan db installation.

On execution, it throws an exception

Exception in thread "main" java.lang.NoSuchMethodError: org.apache.commons.lang.StringUtils.isNotBlank(Ljava/lang/String;)Z

at com.thinkaurelius.titan.graphdb.configuration.KCVSConfiguration.<init>(KCVSConfiguration.java:40)
at com.thinkaurelius.titan.diskstorage.Backend.initialize(Backend.java:273)
at com.thinkaurelius.titan.graphdb.configuration.GraphDatabaseConfiguration.getBackend(GraphDatabaseConfiguration.java:1174)
at com.thinkaurelius.titan.graphdb.database.StandardTitanGraph.<init>(StandardTitanGraph.java:75)
at com.thinkaurelius.titan.core.TitanFactory.open(TitanFactory.java:40)
at com.thinkaurelius.titan.core.TitanFactory.open(TitanFactory.java:29)

Is there a way to resolve this issue?

Answer 1

If you're using a web application with Tomcat , you have to add the jar file into WEB-INF/lib folder of the application (or into $TOMCAT_HOME/lib folder, if you have more webapps using it).

Either create a library with this jar and add it to the project class path.

If you done all this and it still not working, you can change the jar extension to zip or rar and open it to see if the requested classes you need are inside.

Answer 2

Check your classpath for another commons-lang-*.jar. According to the Apache Commons documentation, the isBlank() method is new since 2.0. https://commons.apache.org/proper/commons-lang/javadocs/api-2.5/org/apache/commons/lang/StringUtils.html#isBlank%28java.lang.String%29

Titan 0.4.4 ships with commons-lang-2.5.jar in the lib directory. Your original post didn't mention anything else about the runtime environment. I would suspect that if you had, for example, commons-lang-1.0.1.jar on the classpath, it would be picked up before commons-lang-2.5.jar and you would see the error.