参考资料 http://lfree.itpub.net/post/4950/112308  ；  http://www.itpub.net/602958.html  ； http://blog.csdn.net/chinalinuxzend/archive/2007/09/14/1785634.aspx

                create directory backup as '/home/oracle/backup';  目录得存在
                grant read, write on directory backup to user;

                expdp hr/hr directOry=backp dumpfile=hr1.dmp exclude=TABLE:"IN('T1')"  ；