七月 29, 2017 10:51:00 上午 org.apache.catalina.core.StandardContext listenerStart
嚴重: 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

解決辦法：

            主要是你的zookeeper版本對不上，首先看看你啟動的版本是什麼版本，例如我啟動監聽版本為3.4.11，但是我看了maven依賴引進的是3.4.8版本，因此版本對不上就產生錯誤。這是我修正後顯示的版本，與我啟動版本一致。

修正方法在pom.xml中更新到相應的版本：

<dependency>
        <groupId>org.apache.zookeeper</groupId>
        <artifactId>zookeeper</artifactId>
        <version>你啟動的版本號

發生Error creating bean with name錯誤：

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)
 

很可能是因為你的你的dubbo版本太高，可以適當降低dubbo版本，dubbo版本高，所要求的jdk版本以及其他依賴包的版本也相應變高。所以調一下應該問題不大：

<dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>dubbo</artifactId>
        <version>2.4.9</version>
    </dependency>