使用zookeeper 3.4服务器做为spring cloud的服务注册与发现时出现的异常如下: 

org.apache.zookeeper.KeeperException$UnimplementedException: KeeperErrorCode = Unimplemented for /services/application/c7d9940d-fbb5-474c-a782-52761fb9e682
	at org.apache.zookeeper.KeeperException.create(KeeperException.java:103) ~[zookeeper-3.5.3-beta.jar:3.5.3-beta-8ce24f9e675cbefffb8f21a47e06b42864475a60]
	at org.apache.zookeeper.KeeperException.create(KeeperException.java:51) ~[zookeeper-3.5.3-beta.jar:3.5.3-beta-8ce24f9e675cbefffb8f21a47e06b42864475a60]
	at org.apache.zookeeper.ZooKeeper.create(ZooKeeper.java:1525) ~[zookeeper-3.5.3-beta.jar:3.5.3-beta-8ce24f9e675cbefffb8f21a47e06b42864475a60]
	at org.apache.curator.framework.imps.CreateBuilderImpl$17.call(CreateBuilderImpl.java:1181) ~[curator-framework-4.0.1.jar:4.0.1]
	at org.apache.curator.framework.imps.CreateBuilderImpl$17.call(CreateBuilderImpl.java:1158) ~[curator-framework-4.0.1.jar:4.0.1]
	at org.apache.curator.connection.StandardConnectionHandlingPolicy.callWithRetry(StandardConnectionHandlingPolicy.java:64) ~[curator-client-4.0.1.jar:na]
	at org.apache.curator.RetryLoop.callWithRetry(RetryLoop.java:100) ~[curator-client-4.0.1.jar:na]
	at org.apache.curator.framework.imps.CreateBuilderImpl.pathInForeground(CreateBuilderImpl.java:1155) ~[curator-framework-4.0.1.jar:4.0.1]
	at org.apache.curator.framework.imps.CreateBuilderImpl.protectedPathInForeground(CreateBuilderImpl.java:605) ~[curator-framework-4.0.1.jar:4.0.1]
	at org.apache.curator.framework.imps.CreateBuilderImpl.forPath(CreateBuilderImpl.java:595) ~[curator-framework-4.0.1.jar:4.0.1]
	at org.apache.curator.framework.imps.CreateBuilderImpl.forPath(CreateBuilderImpl.java:49) ~[curator-framework-4.0.1.jar:4.0.1]
	at org.apache.curator.x.discovery.details.ServiceDiscoveryImpl.internalRegisterService(ServiceDiscoveryImpl.java:236) ~[curator-x-discovery-4.0.1.jar:na]
	at org.apache.curator.x.discovery.details.ServiceDiscoveryImpl.reRegisterServices(ServiceDiscoveryImpl.java:456) ~[curator-x-discovery-4.0.1.jar:na]
	at org.apache.curator.x.discovery.details.ServiceDiscoveryImpl.access$100(ServiceDiscoveryImpl.java:58) ~[curator-x-discovery-4.0.1.jar:na]
	at org.apache.curator.x.discovery.details.ServiceDiscoveryImpl$1.stateChanged(ServiceDiscoveryImpl.java:78) ~[curator-x-discovery-4.0.1.jar:na]
	at org.apache.curator.framework.state.ConnectionStateManager$2.apply(ConnectionStateManager.java:274) [curator-framework-4.0.1.jar:4.0.1]
	at org.apache.curator.framework.state.ConnectionStateManager$2.apply(ConnectionStateManager.java:270) [curator-framework-4.0.1.jar:4.0.1]
	at org.apache.curator.framework.listen.ListenerContainer$1.run(ListenerContainer.java:93) [curator-framework-4.0.1.jar:4.0.1]
	at org.apache.curator.shaded.com.google.common.util.concurrent.MoreExecutors$DirectExecutor.execute(MoreExecutors.java:435) [curator-client-4.0.1.jar:na]
	at org.apache.curator.framework.listen.ListenerContainer.forEach(ListenerContainer.java:85) [curator-framework-4.0.1.jar:4.0.1]
	at org.apache.curator.framework.state.ConnectionStateManager.processEvents(ConnectionStateManager.java:268) [curator-framework-4.0.1.jar:4.0.1]
	at org.apache.curator.framework.state.ConnectionStateManager.access$000(ConnectionStateManager.java:44) [curator-framework-4.0.1.jar:4.0.1]
	at org.apache.curator.framework.state.ConnectionStateManager$1.call(ConnectionStateManager.java:120) [curator-framework-4.0.1.jar:4.0.1]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) [na:1.8.0_51]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_51]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_51]
	at java.lang.Thread.run(Thread.java:745) [na:1.8.0_51]

2020-10-02 21:34:32.976  INFO 30926 --- [ain-EventThread] o.a.c.f.state.ConnectionStateManager     : State change: SUSPENDED
2020-10-02 21:34:33.829  INFO 30926 --- [localhost:2181)] org.apache.zookeeper.ClientCnxn          : Opening socket connection to server localhost/127.0.0.1:2181. Will not attempt to authenticate using SASL (unknown error)
2020-10-02 21:34:33.830  INFO 30926 --- [localhost:2181)] org.apache.zookeeper.ClientCnxn          : Socket connection established, initiating session, client: /127.0.0.1:64360, server: localhost/127.0.0.1:2181
2020-10-02 21:34:33.831  INFO 30926 --- [localhost:2181)] org.apache.zookeeper.ClientCnxn          : Session establishment complete on server localhost/127.0.0.1:2181, sessionid = 0x1000c2602c60000, negotiated timeout = 40000
2020-10-02 21:34:33.832  INFO 30926 --- [ain-EventThread] o.a.c.f.state.ConnectionStateManager     : State change: RECONNECTED
2020-10-02 21:34:33.834  INFO 30926 --- [tor-Framework-0] o.a.c.f.imps.CuratorFrameworkImpl        : backgroundOperationsLoop exiting
2020-10-02 21:34:33.838  INFO 30926 --- [  restartedMain] org.apache.zookeeper.ZooKeeper           : Session: 0x1000c2602c60000 closed
2020-10-02 21:34:33.838  INFO 30926 --- [ain-EventThread] org.apache.zookeeper.ClientCnxn          : EventThread shut down for session: 0x1000c2602c60000
2020-10-02 21:34:33.842  INFO 30926 --- [  restartedMain] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'
2020-10-02 21:34:33.855 ERROR 30926 --- [  restartedMain] o.s.boot.SpringApplication               : Application run failed

分析：根据当前引入的maven的依赖分析:

引入的  spring-cloud-starter-zookeeper-discovery2.1.4.RELEASE版依赖于 curator-x-discovery4.0.1,curator是zookeeper的客户端,用于访问zookeeper服务，zookeeper官网描述curator4.0与zookeeper3.4.X有依赖冲突. 

解决方案: 

1. 将 zookeeper3.4升级为 3.5.x版本. 

2. 把项目中的jar包排除再引用和服务器zookeeper一样的版本的jar. 我采用此种方案. 

<!-- 基于zk的服务发现 -->
<dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-zookeeper-discovery</artifactId>
      <!-- 先排除自带的zookeeper3.5.3版本-->
      <exclusions>
           <exclusion>
                <groupId>org.apache.zookeeper</groupId>
                <artifactId>zookeeper</artifactId>
           </exclusion>
      </exclusions>
</dependency>
<!-- 引入和服务器zookeeper一样的版本的jar -->
<dependency>
    <groupId>org.apache.zookeeper</groupId>
    <artifactId>zookeeper</artifactId>
     <version>3.4.14</version>
</dependency>

再重新启动spring clould程序，成功.