我有一个简单的mapreduce程序，我想在远程集群上运行它。我可以从命令行运行

hadoop jar myjar.jar input output

但是，当我想从ide中运行junit testcase类中调用mr作业的函数时，会收到以下警告：

WARN org.apache.hadoop.mapreduce.JobSubmitter  - No job jar file set.  User classes may not be found. See Job or Job#setJar(String).
 INFO org.apache.hadoop.mapred.YARNRunner  - Job jar is not present. Not adding any jar to the list of resources.

虽然我设置了这一行，但在提交mr作业之前：

job.setJarByClass(MyJob.class);

因此作业失败，因为它找不到合适的类（比如mymapkey，它是mapper key类）来操作。

Error: java.io.IOException: Initialization of all the collectors failed. Error in last collector was :java.lang.RuntimeException: java.lang.ClassNotFoundException: Class MyMapKey not found
at org.apache.hadoop.mapred.MapTask.createSortingCollector(MapTask.java:414)
at org.apache.hadoop.mapred.MapTask.access$100(MapTask.java:81)
at org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:698)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:770)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:341)
at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:164)
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:1709)
at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:158)

有什么想法吗？