我是Neo4j的新手，正在尝试探索。 Neo4j Server已启动并正在运行，但是我的Java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" );
}
}
}
但是我遇到以下错误：
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)
答案 0 :(得分：0)
由于错误状态，'message'参数的值未传递到tx.run：Expected parameter(s): message。
填写存根方法parameters的实现后，它应该可以工作：
private Value parameters(String string, String message) {
return Values.parameters( string, message );
}