FileAlreadyExistsException: Output directory hdfs://ubuntu:9000/output09 already exists

14/07/21 17:49:59 ERROR security.UserGroupInformation: PriviledgedActionException as:chenlongquan cause:org.apache.hadoop.mapred.FileAlreadyExistsException: Output directory hdfs://ubuntu:9000/output09 already exists
Exception in thread "main" org.apache.hadoop.mapred.FileAlreadyExistsException: Output directory hdfs://ubuntu:9000/output09 already exists
        at org.apache.hadoop.mapreduce.lib.output.FileOutputFormat.checkOutputSpecs(FileOutputFormat.java:137)
        at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:973)
        at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:936)
        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:1190)
        at org.apache.hadoop.mapred.JobClient.submitJobInternal(JobClient.java:936)
        at org.apache.hadoop.mapreduce.Job.submit(Job.java:550)
        at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:580)
        at com.pzoom.mapred.WordCount.main(WordCount.java:41)
        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.main(RunJar.java:160)

这个错误的大致意思是你所要上传的目录已经存在，在hadoop中仅仅能对文件进行一次上传。不能反复。你要想继续上传，解决方式：1:删除已经存在的目录。2：又一次创建一个目录。