错误信息：
Caused by: org.apache.hadoop.ipc.RemoteException(org.apache.hadoop.security.AccessControlException): Permission denied: user=HHZ, access=WRITE, inode="/mytest/data/song/TO_MINIK_CLIENT_SONG_PLAY_OPERATE_REQ_D":root:supergroup:drwxr-xr-x
解决方法：添加环境变量。完美解决。
详细解读见：http://www.huqiwen.com/2013/07/18/hdfs-permission-denied/