Hbase版本：Hortonworks Hbase 1.1.2
问题描述：
使用Scala操作Hbase时，发生空指针异常（java.lang.RuntimeException: java.lang.NullPointerException），异常如下：
18/09/13 20:28:51 ERROR Executor: Exception in task 1.0 in stage 361.0 (TID 18925) java.lang.RuntimeException: java.lang.NullPointerException at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithoutRetries(RpcRetryingCaller.java:208) at org.apache.hadoop.hbase.client.ClientSmallReversedScanner.loadCache(ClientSmallReversedScanner.java:211) at org.apache.hadoop.hbase.client.ClientSmallReversedScanner.next(ClientSmallReversedScanner.java:185) at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.locateRegionInMeta(ConnectionManager.java:1255) at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.locateRegion(ConnectionManager.java:1161) at org.apache.hadoop.hbase.client.AsyncProcess.submit(AsyncProcess.java:370) at org.apache.hadoop.hbase.client.AsyncProcess.submit(AsyncProcess.java:321) at org.apache.hadoop.hbase.client.BufferedMutatorImpl.backgroundFlushCommits(BufferedMutatorImpl.java:206) at org.apache.hadoop.hbase.client.BufferedMutatorImpl.flush(BufferedMutatorImpl.java:183) at org.apache.hadoop.hbase.client.HTable.flushCommits(HTable.java:1449) at org.apache.hadoop.hbase.client.HTable.put(HTable.java:1052) at scala.OperateMysqlTable$$anonfun$main$1$$anonfun$apply$3$$anonfun$apply$4.apply(AccompanyAnalyze.scala:177) at scala.OperateMysqlTable$$anonfun$main$1$$anonfun$apply$3$$anonfun$apply$4.apply(AccompanyAnalyze.scala:161) at org.apache.spark.rdd.RDD$$anonfun$foreachPartition$1$$anonfun$apply$29.apply(RDD.scala:926) at org.apache.spark.rdd.RDD$$anonfun$foreachPartition$1$$anonfun$apply$29.apply(RDD.scala:926) at org.apache.spark.SparkContext$$anonfun$runJob$5.apply(SparkContext.scala:1954) at org.apache.spark.SparkContext$$anonfun$runJob$5.apply(SparkContext.scala:1954) at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:87) at org.apache.spark.scheduler.Task.run(Task.scala:99) at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:325) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) Caused by: java.lang.NullPointerException at org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher.getMetaReplicaNodes(ZooKeeperWatcher.java:399) at org.apache.hadoop.hbase.zookeeper.MetaTableLocator.blockUntilAvailable(MetaTableLocator.java:552) at org.apache.hadoop.hbase.client.ZooKeeperRegistry.getMetaRegionLocation(ZooKeeperRegistry.java:61) at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.locateMeta(ConnectionManager.java:1191) at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.locateRegion(ConnectionManager.java:1158) at org.apache.hadoop.hbase.client.RpcRetryingCallerWithReadReplicas.getRegionLocations(RpcRetryingCallerWithReadReplicas.java:300) at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:151) at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:59) at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithoutRetries(RpcRetryingCaller.java:200) ... 22 more
问题分析：
该异常为客户端去zookeeper获取Hbase相关信息时，没有找到，抛出空指针异常
问题原因：
不同发行商的hbase的在zookeeper的znode设置不同
Hortonworks的hbase在zookeeper中znode路径为/hbase-unsecure
查看该路径下hbase的相关信息
[zk: localhost:2181(CONNECTED) 1] ls /hbase-unsecure [replication, meta-region-server, rs, splitWAL, backup-masters, table-lock, flush-table-proc, master-maintenance, region-in-transition, online-snapshot, acl, switch, master, running, recovering-regions, draining, namespace, hbaseid, table]
解决办法：
我使用的是Hortonworks的Hbase，所以要在Hbase的conf中添加如下配置信息
conf.set("zookeeper.znode.parent", "/hbase-unsecure")
如果是Cloudera的Hbase，添加配置信息如下：
conf.set("zookeeper.znode.parent", "/hbase")
添加后，重新执行程序，Hbase表创建成功，问题解决
