用Eclipse开发hadoop时报org.apache.hadoop.security.AccessControlException: Permission denied: user=DrWho, access=READ_EXECUTE, inode="system":hadoop:supergroup:rwx-wx-wx错误，解决方法：
在hdfs-site.xml 中取消权限校验，即加入以下配置：
<property>
<name>dfs.permissions</name>
<value>false</value>
<description>
If "true", enable permission checking in HDFS.
If "false", permission checking is turned off,
but all other behavior is unchanged.
Switching from one parameter value to the other does not change the mode,
owner or group of files or directories.
</description>
</property>