org.apache.hadoop.mapred.FileAlreadyExistsException: Output directory hdfs://mycluster/output alread

[hadoop@djtNode1 bin]$ ./hadoop jar ~/app/test/analysis-1.0-SNAPSHOT.jar pv /input/test.txt /output16/04/30 16:25:09 WARN security.UserGroupInformation: PriviledgedActionException as:hadoop (auth:SIMPLE) cause:org.apache.hadoop.mapred.FileAlreadyExistsException: Output directory hdfs://mycluster/output already existsorg.apache.hadoop.mapred.FileAlreadyExistsException: Output directory hdfs://mycluster/output <strong>already exists</strong>at org.apache.hadoop.mapreduce.lib.output.FileOutputFormat.checkOutputSpecs(FileOutputFormat.java:146)at org.apache.hadoop.mapreduce.JobSubmitter.checkSpecs(JobSubmitter.java:562)at org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:432)at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1306)at org.apache.hadoop.mapreduce.Job$10.run(Job.java:1303)at java.security.AccessController.doPrivileged(Native Method)at javax.security.auth.Subject.doAs(Subject.java:422)at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1671)at org.apache.hadoop.mapreduce.Job.submit(Job.java:1303)at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:1324)at com.dajiangtai.Pv.main(Pv.java:67)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:498)at org.apache.hadoop.util.ProgramDriver$ProgramDescription.invoke(ProgramDriver.java:71)at org.apache.hadoop.util.ProgramDriver.run(ProgramDriver.java:144)at com.dajiangtai.MyDriver.main(MyDriver.java:25)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:498)at org.apache.hadoop.util.RunJar.run(RunJar.java:221)at org.apache.hadoop.util.RunJar.main(RunJar.java:136)

该问题是因为在hdfs中已经存在了 /output文件夹，将其删除，重新运行即可。