七月 29, 2017 10:51:00 上午 org.apache.catalina.core.StandardContext listenerStart
严重: Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener
java.lang.NoClassDefFoundError: org/apache/zookeeper/Watcher$Event$KeeperState
at com.alibaba.dubbo.remoting.zookeeper.zkclient.ZkclientZookeeperClient.<init>(ZkclientZookeeperClient.java:21)
at com.alibaba.dubbo.remoting.zookeeper.zkclient.ZkclientZookeeperTransporter.connect(ZkclientZookeeperTransporter.java:10)
at com.alibaba.dubbo.remoting.zookeeper.ZookeeperTransporter$Adpative.connect(ZookeeperTransporter$Adpative.java)
at com.alibaba.dubbo.registry.zookeeper.ZookeeperRegistry.<init>(ZookeeperRegistry.java:71)
at com.alibaba.dubbo.registry.zookeeper.ZookeeperRegistryFactory.createRegistry(ZookeeperRegistryFactory.java:37
解决办法：
主要是你的zookeeper版本对不上，首先看看你启动的版本是什么版本，例如我启动监听版本为3.4.11，但是我看了maven依赖引进的是3.4.8版本，因此版本对不上就产生错误。这是我修正后显示的版本，与我启动版本一致。
修正方法在pom.xml中更新到相应的版本：
<dependency>
<groupId>org.apache.zookeeper</groupId>
<artifactId>zookeeper</artifactId>
<version>你启动的版本号</version>
</dependency>
发生Error creating bean with name错误：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.test.dubboser3.service.UserService': Instantiation of bean failed; nested exception is java.lang.ExceptionInInitializerError
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1105)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1050)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:510)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:305)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:301)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:196)
很可能是因为你的你的dubbo版本太高，可以适当降低dubbo版本，dubbo版本高，所要求的jdk版本以及其他依赖包的版本也相应变高。所以调一下应该问题不大：
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>dubbo</artifactId>
<version>2.4.9</version>
</dependency>