1：expdp利用dblink将远程数据导出到本地
expdp local_user/xxxxxx network_link=local_to_server directory=DUMPDIR dumpfile=file.dmp logfile=file.log SCHEMAS=user1
DUMPDIR 为本地directory目录
2：使用impdp network link 跳过expdp直接导入数据
impdp local_user/xxxxxx directory=DUMPDIR logfile=remote_to_local.log network_link=remote_to_local schemas=user01 remap_schema=user01:user02
DUMPDIR 为本地directory目录