无法从Java客户端连接Neo4j

Question

我是Neo4j的新手，正在尝试探索。Java已启动并运行，但我的Neo4j客户端无法连接。

这是我的代码：

public class neojdbc implements AutoCloseable
{
    private Driver driver;

    public neojdbc(String uri, String user, String password) {

        Config config = Config.builder()
                .withMaxConnectionLifetime( 30, TimeUnit.MINUTES )
                .withMaxConnectionPoolSize( 50 )
                .withConnectionAcquisitionTimeout( 2, TimeUnit.MINUTES )
                .withTrustStrategy( Config.TrustStrategy.trustAllCertificates() )
                .withoutEncryption()
                .build(); 

        driver = GraphDatabase.driver( uri, AuthTokens.basic( user, password ), config );


    }

    @Override
    public void close() throws Exception
    {
        driver.close();
    }

    public void printGreeting( final String message )
    {
        try ( Session session = driver.session() )
        {
            String greeting = session.writeTransaction( new TransactionWork<String>()
            {
                @Override
                public String execute( Transaction tx )
                {
                    StatementResult result = tx.run( "CREATE (a:Greeting) " +
                                                     "SET a.message = $message " +
                                                     "RETURN a.message + ', from node ' + id(a)",parameters( "message", message ) );
                    return result.single().get( 0 ).asString();
                }

                private Value parameters(String string, String message) {
                    // TODO Auto-generated method stub
                    return null;
                }
            } );
            System.out.println( greeting );
        }
    }


    public static void main( String... args ) throws Exception
    {
        try ( neojdbc greeter = new neojdbc("bolt://172.XX.XX.XX:7687", "neo4j", "admin" ) )
        {
            greeter.printGreeting( "hello, world" );
        }
    }


}

然而，我得到了以下错误：

Exception in thread "main" org.neo4j.driver.v1.exceptions.ClientException: Expected parameter(s): message
    at org.neo4j.driver.internal.util.Futures.blockingGet(Futures.java:123)
    at org.neo4j.driver.internal.InternalStatementResult.blockingGet(InternalStatementResult.java:134)
    at org.neo4j.driver.internal.InternalStatementResult.single(InternalStatementResult.java:81)
    at tryssl.sslneo.neojdbc$1.execute(neojdbc.java:55)
    at tryssl.sslneo.neojdbc$1.execute(neojdbc.java:1)
    at org.neo4j.driver.internal.NetworkSession.lambda$transaction$10(NetworkSession.java:322)
    at org.neo4j.driver.internal.retry.ExponentialBackoffRetryLogic.retry(ExponentialBackoffRetryLogic.java:93)
    at org.neo4j.driver.internal.NetworkSession.transaction(NetworkSession.java:316)
    at org.neo4j.driver.internal.NetworkSession.writeTransaction(NetworkSession.java:236)
    at org.neo4j.driver.internal.NetworkSession.writeTransaction(NetworkSession.java:230)
    at tryssl.sslneo.neojdbc.printGreeting(neojdbc.java:47)
    at tryssl.sslneo.neojdbc.main(neojdbc.java:72)
    Suppressed: org.neo4j.driver.internal.util.ErrorUtil$InternalExceptionCause
        at org.neo4j.driver.internal.util.ErrorUtil.newNeo4jError(ErrorUtil.java:67)
        at org.neo4j.driver.internal.async.inbound.InboundMessageDispatcher.handleFailureMessage(InboundMessageDispatcher.java:105)
        at org.neo4j.driver.internal.messaging.v1.MessageReaderV1.unpackFailureMessage(MessageReaderV1.java:83)
        at org.neo4j.driver.internal.messaging.v1.MessageReaderV1.read(MessageReaderV1.java:59)
        at org.neo4j.driver.internal.async.inbound.InboundMessageHandler.channelRead0(InboundMessageHandler.java:83)
        at org.neo4j.driver.internal.async.inbound.InboundMessageHandler.channelRead0(InboundMessageHandler.java:35)
        at org.neo4j.driver.internal.shaded.io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:105)
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
        at org.neo4j.driver.internal.shaded.io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:310)
        at org.neo4j.driver.internal.shaded.io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:284)
        at org.neo4j.driver.internal.async.inbound.MessageDecoder.channelRead(MessageDecoder.java:47)
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
        at org.neo4j.driver.internal.shaded.io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:310)
        at org.neo4j.driver.internal.shaded.io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:297)
        at org.neo4j.driver.internal.shaded.io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:413)
        at org.neo4j.driver.internal.shaded.io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:265)
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
        at org.neo4j.driver.internal.shaded.io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1414)
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
        at org.neo4j.driver.internal.shaded.io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:945)
        at org.neo4j.driver.internal.shaded.io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:146)
        at org.neo4j.driver.internal.shaded.io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:645)
        at org.neo4j.driver.internal.shaded.io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:580)
        at org.neo4j.driver.internal.shaded.io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:497)
        at org.neo4j.driver.internal.shaded.io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:459)
        at org.neo4j.driver.internal.shaded.io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:886)
        at org.neo4j.driver.internal.shaded.io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.lang.Thread.run(Thread.java:748)

Answer 1

正如错误所述，'message‘参数的值不会传递给tx.run：Expected parameter(s): message。

一旦填充了存根方法parameters的实现，它就应该可以工作了：

 private Value parameters(String string, String message) {
     return Values.parameters( string, message );
 }