线程＆＃34; main＆＃34;中的例外情况java.lang.NoClassDefFoundError：org / neo4j / function / Function

Question

我有以下应用程序连接到neo4j db：

package graphdb;

import java.io.File;
import java.io.IOException;

import org.neo4j.graphdb.Direction;
import org.neo4j.graphdb.GraphDatabaseService;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.Relationship;
import org.neo4j.graphdb.RelationshipType;
import org.neo4j.graphdb.Transaction;
import org.neo4j.graphdb.factory.GraphDatabaseFactory;
import org.neo4j.io.fs.FileUtils;

/**
 *
 * @author bma
 */
public class Graphdb {

    private static final String DB_PATH = "D:\\Data";

    public String greeting;

    // START SNIPPET: vars
    GraphDatabaseService graphDb;
    Node firstNode;
    Node secondNode;
    Relationship relationship;
    // END SNIPPET: vars

    // START SNIPPET: createReltype
    private static enum RelTypes implements RelationshipType
    {
        KNOWS
    }
    // END SNIPPET: createReltype

    public static void main( final String[] args ) throws IOException
    {
        Graphdb hello = new Graphdb();
        hello.createDb();
        hello.removeData();
        hello.shutDown();
    }

    void createDb() throws IOException
    {
        FileUtils.deleteRecursively( new File( DB_PATH ) );

        // START SNIPPET: startDb
        graphDb = new GraphDatabaseFactory().newEmbeddedDatabase( DB_PATH );
        registerShutdownHook( graphDb );
        // END SNIPPET: startDb

        // START SNIPPET: transaction
        try ( Transaction tx = graphDb.beginTx() )
        {
            // Database operations go here
            // END SNIPPET: transaction
            // START SNIPPET: addData
            firstNode = graphDb.createNode();
            firstNode.setProperty( "message", "Hello, " );
            secondNode = graphDb.createNode();
            secondNode.setProperty( "message", "World!" );

            relationship = firstNode.createRelationshipTo( secondNode, RelTypes.KNOWS );
            relationship.setProperty( "message", "brave Neo4j " );
            // END SNIPPET: addData

            // START SNIPPET: readData
            System.out.print( firstNode.getProperty( "message" ) );
            System.out.print( relationship.getProperty( "message" ) );
            System.out.print( secondNode.getProperty( "message" ) );
            // END SNIPPET: readData

            greeting = ( (String) firstNode.getProperty( "message" ) )
                       + ( (String) relationship.getProperty( "message" ) )
                       + ( (String) secondNode.getProperty( "message" ) );

            // START SNIPPET: transaction
            tx.success();
        }
        // END SNIPPET: transaction
    }

    void removeData()
    {
        try ( Transaction tx = graphDb.beginTx() )
        {
            // START SNIPPET: removingData
            // let's remove the data
            firstNode.getSingleRelationship( RelTypes.KNOWS, Direction.OUTGOING ).delete();
            firstNode.delete();
            secondNode.delete();
            // END SNIPPET: removingData

            tx.success();
        }
    }

    void shutDown()
    {
        System.out.println();
        System.out.println( "Shutting down database ..." );
        // START SNIPPET: shutdownServer
        graphDb.shutdown();
        // END SNIPPET: shutdownServer
    }

    // START SNIPPET: shutdownHook
    private static void registerShutdownHook( final GraphDatabaseService graphDb )
    {
        // Registers a shutdown hook for the Neo4j instance so that it
        // shuts down nicely when the VM exits (even if you "Ctrl-C" the
        // running application).
        Runtime.getRuntime().addShutdownHook( new Thread()
        {
            @Override
            public void run()
            {
                graphDb.shutdown();
            }
        } );
    }

}

当我尝试编译时，我收到了以下错误信息：

run:
Exception in thread "main" java.lang.NoClassDefFoundError: org/neo4j/function/Function
    at org.neo4j.graphdb.factory.GraphDatabaseFactory.createGraphDatabaseBuilder(GraphDatabaseFactory.java:99)
    at org.neo4j.graphdb.factory.GraphDatabaseFactory.newEmbeddedDatabaseBuilder(GraphDatabaseFactory.java:92)
    at org.neo4j.graphdb.factory.GraphDatabaseFactory.newEmbeddedDatabase(GraphDatabaseFactory.java:76)
    at org.neo4j.graphdb.factory.GraphDatabaseFactory.newEmbeddedDatabase(GraphDatabaseFactory.java:71)
    at graphdb.Graphdb.createDb(Graphdb.java:57)
    at graphdb.Graphdb.main(Graphdb.java:47)
Caused by: java.lang.ClassNotFoundException: org.neo4j.function.Function
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 6 more
Java Result: 1
BUILD SUCCESSFUL (total time: 0 seconds)

我做错了什么？ 正如你在图片中看到的，添加了neo4j库。

Answer 1

您似乎必须将库org.neo4j.graphdb添加到类路径中。

可能是jar neo4j-kernel-2.2.2.jar

或者如果您正在使用maven，请添加工件：

<dependency>
  <groupId>org.neo4j</groupId>
  <artifactId>neo4j-kernel</artifactId>
  <version>2.2.2</version>
</dependency>