Java Cassandra单元示例中的TransportException

什么是例外？我尝试了Cassandra单元示例，并且能够运行该示例。示例中的单元测试通过了，但我在为我的项目配置Cassandra单元时遇到了问题。然而，我遇到了一个例外：

2014-09-19 13:49:15,932 [New I/O worker #35] DEBUG driver.core.Connection - Defuncting connection to /127.0.0.1
com.datastax.driver.core.TransportException: [/127.0.0.1] Channel has been closed
    at com.datastax.driver.core.Connection$Dispatcher.channelClosed(Connection.java:622)
    at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:88)
    at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)
    at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791)
    at org.jboss.netty.handler.codec.oneone.OneToOneDecoder.handleUpstream(OneToOneDecoder.java:60)
    at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)
    at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791)
    at org.jboss.netty.handler.codec.frame.FrameDecoder.cleanup(FrameDecoder.java:493)
    at org.jboss.netty.handler.codec.frame.FrameDecoder.channelClosed(FrameDecoder.java:371)
    at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:88)
    at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)
    at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:559)
    at org.jboss.netty.channel.Channels.fireChannelClosed(Channels.java:468)
    at org.jboss.netty.channel.socket.nio.AbstractNioWorker.close(AbstractNioWorker.java:375)
    at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:93)
    at org.jboss.netty.channel.socket.nio.AbstractNioWorker.process(AbstractNioWorker.java:108)
    at org.jboss.netty.channel.socket.nio.AbstractNioSelector.run(AbstractNioSelector.java:318)
    at org.jboss.netty.channel.socket.nio.AbstractNioWorker.run(AbstractNioWorker.java:89)
    at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:178)
    at org.jboss.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108)
    at org.jboss.netty.util.internal.DeadLockProofWorker$1.run(DeadLockProofWorker.java:42)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)