我有一个mapreduce程序，其中我利用Hcatalog从Hive表' a '中获取HcatInputFormat的详细信息，处理它并使用HcatOutput格式将其写回Hive表'B'
我使用eclipse编写程序，并从项目中创建了一个可运行的'Hadooptest' jar，并在hadoop集群中使用hadoop jar命令运行该jar(带-libjars参数
)。当我将所有引用的jar提取到jar文件中创建可运行的jar，然后在hadoop集群中执行时，mapreduce运行良好并成功完成。
问题是，当我使用"复制所需的库到生成的jar旁边的子文件夹"选项创建可运行的jar时，然后将jar和引用的库都移动到hadoop集群，并执行它，它显示
" org.apache.hadoop.yarn.exceptions.YarnRuntimeException:java.lang.RuntimeException: java.lang.ClassNotFoundException: Class"
下面是完整的纱线日志:
2016-06-29 12:17:57,951 INFO [main] org.apache.hadoop.mapreduce.v2.app.MRAppMaster: Created MRAppMaster for application appattempt_1466834505106_0057_000002
2016-06-29 12:17:58,672 WARN [main] org.apache.hadoop.util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
2016-06-29 12:17:58,773 INFO [main] org.apache.hadoop.mapreduce.v2.app.MRAppMaster: Executing with tokens:
2016-06-29 12:17:58,773 INFO [main] org.apache.hadoop.mapreduce.v2.app.MRAppMaster: Kind: YARN_AM_RM_TOKEN, Service: , Ident: (appAttemptId { application_id { id: 57 cluster_timestamp: 1466834505106 } attemptId: 2 } keyId: 783034855)
2016-06-29 12:17:58,974 INFO [main] org.apache.hadoop.mapreduce.v2.app.MRAppMaster: Using mapred newApiCommitter.
2016-06-29 12:17:59,840 INFO [main] org.apache.hadoop.mapreduce.v2.app.MRAppMaster: OutputCommitter set in config null
2016-06-29 12:17:59,920 INFO [main] org.apache.hadoop.service.AbstractService: Service org.apache.hadoop.mapreduce.v2.app.MRAppMaster failed in state INITED; cause: org.apache.hadoop.yarn.exceptions.YarnRuntimeException: java.lang.RuntimeException: java.lang.ClassNotFoundException: Class org.apache.hive.hcatalog.mapreduce.HCatOutputFormat not found
org.apache.hadoop.yarn.exceptions.YarnRuntimeException: java.lang.RuntimeException: java.lang.ClassNotFoundException: Class org.apache.hive.hcatalog.mapreduce.HCatOutputFormat not found
at org.apache.hadoop.mapreduce.v2.app.MRAppMaster$1.call(MRAppMaster.java:472)
at org.apache.hadoop.mapreduce.v2.app.MRAppMaster$1.call(MRAppMaster.java:452)
at org.apache.hadoop.mapreduce.v2.app.MRAppMaster.callWithJobClassLoader(MRAppMaster.java:1538)
at org.apache.hadoop.mapreduce.v2.app.MRAppMaster.createOutputCommitter(MRAppMaster.java:452)
at org.apache.hadoop.mapreduce.v2.app.MRAppMaster.serviceInit(MRAppMaster.java:371)
at org.apache.hadoop.service.AbstractService.init(AbstractService.java:163)
at org.apache.hadoop.mapreduce.v2.app.MRAppMaster$4.run(MRAppMaster.java:1496)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1657)
at org.apache.hadoop.mapreduce.v2.app.MRAppMaster.initAndStartAppMaster(MRAppMaster.java:1493)
at org.apache.hadoop.mapreduce.v2.app.MRAppMaster.main(MRAppMaster.java:1426)
Caused by: java.lang.RuntimeException: java.lang.ClassNotFoundException: Class org.apache.hive.hcatalog.mapreduce.HCatOutputFormat not found
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:2195)
at org.apache.hadoop.mapreduce.task.JobContextImpl.getOutputFormatClass(JobContextImpl.java:222)
at org.apache.hadoop.mapreduce.v2.app.MRAppMaster$1.call(MRAppMaster.java:468)
... 11 more
Caused by: java.lang.ClassNotFoundException: Class org.apache.hive.hcatalog.mapreduce.HCatOutputFormat not found
at org.apache.hadoop.conf.Configuration.getClassByName(Configuration.java:2101)
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:2193)
... 13 more
End of LogType:syslog
并且有必要将需要的库导出到单独的文件夹中，而不是解压缩到jar本身。
所有的jar都已经存在于你的hadoop集群中，你只需要将它们的位置传递给你的程序，这在官方文档中提到:
export HADOOP_HOME=<path_to_hadoop_install>
export HCAT_HOME=<path_to_hcat_install>
export HIVE_HOME=<path_to_hive_install>
export LIB_JARS=$HCAT_HOME/share/hcatalog/hcatalog-core-0.5.0.jar,
$HIVE_HOME/lib/hive-metastore-0.10.0.jar,
$HIVE_HOME/lib/libthrift-0.7.0.jar,
$HIVE_HOME/lib/hive-exec-0.10.0.jar,
$HIVE_HOME/lib/libfb303-0.7.0.jar,
$HIVE_HOME/lib/jdo2-api-2.3-ec.jar,
$HIVE_HOME/lib/slf4j-api-1.6.1.jar
export HADOOP_CLASSPATH=$HCAT_HOME/share/hcatalog/hcatalog-core-0.5.0.jar:
$HIVE_HOME/lib/hive-metastore-0.10.0.jar:
$HIVE_HOME/lib/libthrift-0.7.0.jar:
$HIVE_HOME/lib/hive-exec-0.10.0.jar:
$HIVE_HOME/lib/libfb303-0.7.0.jar:
$HIVE_HOME/lib/jdo2-api-2.3-ec.jar:
$HIVE_HOME/conf:$HADOOP_HOME/conf:
$HIVE_HOME/lib/slf4j-api-1.6.1.jar
$HADOOP_HOME/bin/hadoop --config $HADOOP_HOME/conf jar <path_to_jar>
<main_class> -libjars $LIB_JARS <program_arguments>