ES5.1 transportClient 获取链接

用 TransportClient (5.1版本)获取链接的 报错， 内容如下：
Exception in thread "main" java.lang.NoClassDefFoundError: org/elasticsearch/transport/Netty3Plugin
at org.elasticsearch.transport.client.PreBuiltTransportClient.<clinit>(PreBuiltTransportClient.java:54)
at javacommon.util.es.ESTransportClient.createClient(ESTransportClient.java:64)
at javacommon.util.es.ESTransportClient.getTransportClient(ESTransportClient.java:87)
at javacommon.util.es.ESAdminClient.<clinit>(ESAdminClient.java:11)
Caused by: java.lang.ClassNotFoundException: org.elasticsearch.transport.Netty3Plugin
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 4 more
 
 
 
请问是怎么回事呢