Exception in thread “main“ java.lang.NullPointerException at com.zs.zookeeper.DistributeServer.reg(代

Posted 2021-10-17 ZSYL

Exception in thread "main" java.lang.NullPointerException

• 问题描述
• 解决方案

问题描述

执行ZooKeeper-Java主程序代码时，发生空指针异常：

Exception in thread "main" java.lang.NullPointerException
	at com.zs.zookeeper.DistributeServer.regist(DistributeServer.java:30)
	at com.zs.zookeeper.DistributeServer.main(DistributeServer.java:16)

解决方案

原来是代码有误：

private ZooKeeper zkClient;

private void getConnect() throws IOException {

   ZooKeeper zkClient = new ZooKeeper(connectString, sessionTimeout, new Watcher() {
       @Override
       public void process(WatchedEvent watchedEvent) {

       }
   });

我在方法外面声明了全局变量zkClient，之后又再方法内声明重名的局部变量，导致全局变量未被初始化，因此空指针异常报错。

hadoop102 is online...

去除之后就行了！

加油!

感谢!

努力!