dubbo-samples-spring-boot 启动失败，报错：

2022-09-18 22:20:19.982  WARN 6344 --- [127.0.0.1:2181)] org.apache.zookeeper.ClientCnxn          : Session 0x0 for server 127.0.0.1/<unresolved>:2181, unexpected error, closing socket connection and attempting reconnect

java.lang.IllegalArgumentException: Unable to canonicalize address 127.0.0.1/<unresolved>:2181 because it's not resolvable
    at org.apache.zookeeper.SaslServerPrincipal.getServerPrincipal(SaslServerPrincipal.java:65) ~[zookeeper-3.4.14.jar:3.4.14-4c25d480e66aadd371de8bd2fd8da255ac140bcf]
    at org.apache.zookeeper.SaslServerPrincipal.getServerPrincipal(SaslServerPrincipal.java:41) ~[zookeeper-3.4.14.jar:3.4.14-4c25d480e66aadd371de8bd2fd8da255ac140bcf]
    at org.apache.zookeeper.ClientCnxn$SendThread.startConnect(ClientCnxn.java:1001) ~[zookeeper-3.4.14.jar:3.4.14-4c25d480e66aadd371de8bd2fd8da255ac140bcf]
    at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1060) ~[zookeeper-3.4.14.jar:3.4.14-4c25d480e66aadd371de8bd2fd8da255ac140bcf]

解决问题：jdk版本问题，换成jdk8就行了。
 

问题原因分析

看Zookeeper类的构造函数，这里用的是 ConnectStringParser 类来解析地址

ConnectStringParser里面又是用的又是 InetSocketAddress.createUnresolved(host, port)这个方法

InetSocketAddress.createUnresolved(host, port)

这里没什么问题，问题在于InetSocketAddress的toString方法，这个方法，在jdk8和jdk17有差异，在jdk17中，如果传入的addr为空就会拼一个/<unresolved>上去。。。。

        
       // jdk8

        private boolean isUnresolved() {
            return addr == null;
        }

        @Override
        public String toString() {
            if (isUnresolved()) {
                return hostname + ":" + port;
            } else {
                return addr.toString() + ":" + port;
            }
        }

// jdk17

        private boolean isUnresolved() {
            return addr == null;
        }

        @Override
        public String toString() {

            String formatted;

            if (isUnresolved()) {
                formatted = hostname + "/<unresolved>";
            } else {
                formatted = addr.toString();
                if (addr instanceof Inet6Address) {
                    int i = formatted.lastIndexOf("/");
                    formatted = formatted.substring(0, i + 1)
                            + "[" + formatted.substring(i + 1) + "]";
                }
            }
            return formatted + ":" + port;
        }