我的zookeeper是安裝在本地，用的默認端口2181，版本3.4.10。dubbo版本2.5.8。
dubbo-demo-provider.xml配置文件修改為：
<dubbo:registry address="zookeeper://127.0.0.1:2181"/>
運行Provider就會報下面的錯：
[24/12/17 04:56:57:057 CST] main ERROR zkclient.ZkClientWrapper: [DUBBO] Timeout! zookeeper server can not be connected in : 30000ms!, dubbo version: 2.0.0, current host: 127.0.0.1
最后導致
Caused by: java.lang.IllegalStateException: Zookeeper is not connected yet!
at com.alibaba.dubbo.remoting.zookeeper.zkclient.ZkClientWrapper.createPersistent(ZkClientWrapper.java:82)
at com.alibaba.dubbo.remoting.zookeeper.zkclient.ZkclientZookeeperClient.createPersistent(ZkclientZookeeperClient.java:45)
at com.alibaba.dubbo.remoting.zookeeper.support.AbstractZookeeperClient.create(AbstractZookeeperClient.java:47)
at com.alibaba.dubbo.remoting.zookeeper.support.AbstractZookeeperClient.create(AbstractZookeeperClient.java:41)
at com.alibaba.dubbo.remoting.zookeeper.support.AbstractZookeeperClient.create(AbstractZookeeperClient.java:41)
at com.alibaba.dubbo.remoting.zookeeper.support.AbstractZookeeperClient.create(AbstractZookeeperClient.java:41)
at com.alibaba.dubbo.registry.zookeeper.ZookeeperRegistry.doRegister(ZookeeperRegistry.java:110)
... 21 more
求解答，非常感謝！
解決辦法：
1，檢查jdk版本，jdk1.6 dubbo 2.5版本，2.6版本則使用jdk1.8，dubbo的版本過高或者過低的原因！
2，配置zookeeper中的配置文件，配置超時時間，配大一點！