java - 运行jar时出现ClassNotFoundException，尽管它包含所有类

Question

我已经为jar作业使用eclipse创建了mapreduce。如果您提取jar，则可以看到那里所有的类。当您在run hadoop`命令中对jar进行hadoop``using时，它显示以下错误。

它不能仅识别一个类，即Test_project$TwoDArrayWritables。 Test_project是main类，而TwoDArrayWritables是class中的Test_project。 TwoDArrayWritables继承TwoDArrayWritable中的hadoop内置类。

Jar提取图片:



错误:

16/04/05 15:48:28 INFO mapred.JobClient: Task Id : attempt_201604051120_0002_m_000000_1, Status : FAILED
java.lang.RuntimeException: java.lang.RuntimeException: java.lang.ClassNotFoundException: mapreduce.Test_project$TwoDArrayWritables
    at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:889)
    at org.apache.hadoop.mapred.JobConf.getMapOutputValueClass(JobConf.java:747)
    at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.<init>(MapTask.java:966)
    at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:422)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:366)
    at org.apache.hadoop.mapred.Child$4.run(Child.java:255)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:422)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1190)
    at org.apache.hadoop.mapred.Child.main(Child.java:249)
Caused by: java.lang.RuntimeException: java.lang.ClassNotFoundException: mapreduce.Test_project$TwoDArrayWritables
    at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:857)
    at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:881)
    ... 9 more
Caused by: java.lang.ClassNotFoundException: mapreduce.Test_project$TwoDArrayWritables
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:348)
    at org.apache.hadoop.conf.Configuration.getClassByName(Configuration.java:810)
    at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:855)
    ... 10 more

16/04/05 15:48:34 INFO mapred.JobClient: Task Id : attempt_201604051120_0002_m_000000_2, Status : FAILED
java.lang.RuntimeException: java.lang.RuntimeException: java.lang.ClassNotFoundException: mapreduce.Test_project$TwoDArrayWritables
    at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:889)
    at org.apache.hadoop.mapred.JobConf.getMapOutputValueClass(JobConf.java:747)
    at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.<init>(MapTask.java:966)
    at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:422)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:366)
    at org.apache.hadoop.mapred.Child$4.run(Child.java:255)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:422)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1190)
    at org.apache.hadoop.mapred.Child.main(Child.java:249)
Caused by: java.lang.RuntimeException: java.lang.ClassNotFoundException: mapreduce.Test_project$TwoDArrayWritables
    at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:857)
    at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:881)
    ... 9 more
Caused by: java.lang.ClassNotFoundException: mapreduce.Test_project$TwoDArrayWritables
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:348)
    at org.apache.hadoop.conf.Configuration.getClassByName(Configuration.java:810)
    at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:855)
    ... 10 more

Google搜索了许多解决方案，但没有任何效果。请帮忙!

Answer 1

试试这个:bin/hadoop jar /path/to/jarfile/newproj.jar Test_project.TwoDArrayWritables /user/hduser/input /user/hduser/output1