#问题描述
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使用hadoop命令执行hbase应用jar包时，报如下错误：
[hadoop@ breath ~]$ hadoop jar ~/HbaseTest-0.1.jar Test.HtableCreate Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/hadoop/hbase/HBaseConfiguration at Test.HtableCreate.main(HtableCreate.java:21) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at org.apache.hadoop.util.RunJar.run(RunJar.java:221) at org.apache.hadoop.util.RunJar.main(RunJar.java:136) Caused by: java.lang.ClassNotFoundException: org.apache.hadoop.hbase.HBaseConfiguration at java.net.URLClassLoader$1.run(URLClassLoader.java:366) at java.net.URLClassLoader$1.run(URLClassLoader.java:355) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:354) at java.lang.ClassLoader.loadClass(ClassLoader.java:425) at java.lang.ClassLoader.loadClass(ClassLoader.java:358) ... 7 more
#问题分析
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查看hadoop的classpath发现并无hbase的相关依赖jar包
[hadoop@ breath ~]$ hadoop classpath /opt/beh/core/hadoop/etc/hadoop:/opt/beh/core/hadoop/share/hadoop/common/lib/:/opt/beh/core/hadoop/share/hadoop/common/:/opt/beh/core/hadoop/share/hadoop/hdfs:/opt/beh/core/hadoop/share/hadoop/hdfs/lib/:/opt/beh/core/hadoop/share/hadoop/hdfs/:/opt/beh/core/hadoop/share/hadoop/yarn/lib/:/opt/beh/core/hadoop/share/hadoop/yarn/:/opt/beh/core/hadoop/share/hadoop/mapreduce/lib/:/opt/beh/core/hadoop/share/hadoop/mapreduce/:/opt/beh/core/hadoop/contrib/capacity-scheduler/*.jar
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尝试在在环境变量CLASSPATH中添加$HBASE_HOME/lib/*无效。
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查看Hbase官方文档中"HBase and MapReduce"-"HBase, MapReduce, and the CLASSPATH"详细解释了MapReduce与Hbase jar执行的关系
如果临时使用环境变量可如下设置：
HADOOP_CLASSPATH=`${HBASE_HOME}/bin/hbase classpath` ${HADOOP_HOME}/bin/hadoop jar ${HBASE_HOME}/lib/hbase-examples-VERSION.jar 如果永久生效可以在hadoop-env.sh中设置HADOOP_CLASSPATH,如下设置：
# Extra Java CLASSPATH elements. Automatically insert capacity-scheduler.if [ -z $HBASE_HOME ];then export HADOOP_CLASSPATH=${HADOOP_CLASSPATH}else export HADOOP_CLASSPATH=${HADOOP_CLASSPATH}:${HBASE_HOME}/lib'/*'fi