1.在使用hbase的时候 有很多问题，其中一个
使用sqoop import 从mysql 向hbase导入数据，报错：Error: java.lang.RuntimeException: Could not access HBase table user
执行：sqoop import --connect jdbc:mysql://localhost:3306/social --username root --password root --table user --split-by id --hbase-table user --column-family person
报错：
Error: java.lang.RuntimeException: Could not access HBase table user
at org.apache.sqoop.hbase.HBasePutProcessor.setConf(HBasePutProcessor.java:97)
at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:73)
at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:133)
at org.apache.sqoop.mapreduce.DelegatingOutputFormat$DelegatingRecordWriter.<init>(DelegatingOutputFormat.java:107)
at org.apache.sqoop.mapreduce.DelegatingOutputFormat.getRecordWriter(DelegatingOutputFormat.java:82)
at org.apache.hadoop.mapred.MapTask$NewDirectOutputCollector.<init>(MapTask.java:624)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:744)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:340)
at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:168)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:422)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1614)
at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:163)
Caused by: java.io.IOException: java.lang.reflect.InvocationTargetException
at org.apache.hadoop.hbase.client.ConnectionFactory.createConnection(ConnectionFactory.java:240)
at org.apache.hadoop.hbase.client.ConnectionManager.createConnection(ConnectionManager.java:431)
at org.apache.hadoop.hbase.client.ConnectionManager.createConnection(ConnectionManager.java:424)
at org.apache.hadoop.hbase.client.ConnectionManager.getConnectionInternal(ConnectionManager.java:302)
at org.apache.hadoop.hbase.client.HTable.<init>(HTable.java:185)
at org.apache.hadoop.hbase.client.HTable.<init>(HTable.java:151)
at org.apache.sqoop.hbase.HBasePutProcessor.setConf(HBasePutProcessor.java:95)
... 12 more
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at org.apache.hadoop.hbase.client.ConnectionFactory.createConnection(ConnectionFactory.java:238)
... 18 more
Caused by: java.lang.NoClassDefFoundError: io/netty/channel/EventLoopGroup
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:348)
at org.apache.hadoop.conf.Configuration.getClassByNameOrNull(Configuration.java:1844)
at org.apache.hadoop.conf.Configuration.getClassByName(Configuration.java:1809)
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:1903)
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:1929)
at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.<init>(ConnectionManager.java:656)
... 23 more
Caused by: java.lang.ClassNotFoundException: io.netty.channel.EventLoopGroup
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 30 more
我的解决方案： 我查看了我的表 user 确实已经在hbase存在了。然后查看我的sqoop/lib/ 下jar netty-all-4.0.23.Final.jar,也已经存在， 然后我用gui 去反编译jar 打开后是没有 io/netty/channel/EventLoopGroup。
然后重新下载了一个 netty-all-4.0.23.Final.jar 然后执行命令 。数据可以正确的导入.