不指定数据库可以正常连接：
指定数据库和使用PL/SQL Developer都出现错误：vcD4KPHA+PGltZyBzcmM9″/uploadfile/Collfiles/20140604/2014060408581614.jpg” alt=”N\{?/魫,7痾Z)z?i蒦遫棣薻?糙铻楗╧y”/database/Oracle/” target=”_blank” class=”keylink”>Oracle主服务和监听服务。
解决方案二：（可行）
既然listener.ora中没有指定监听，我可可以在listener.ora文件中指定监听的实例名，这样应该可以连接。
oracle账号在Oracle的安装目录中搜索到listener.ora文件然后做如下的添加，保存重启相应的服务即可。
# listener.ora Network Configuration File: D:\app\Administrator\product\11.2.0\dbhome_1\network\admin\listener.ora
# Generated by Oracle configuration tools.
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = CLRExtProc)
(ORACLE_HOME = D:\app\Administrator\product\11.2.0\dbhome_1)
(PROGRAM = extproc)
(ENVS = "EXTPROC_DLLS=ONLY:D:\app\Administrator\product\11.2.0\dbhome_1\bin\oraclr11.dll")
)
(SID_DESC =
(GLOBAL_DBNAME = ORCL)
(ORACLE_HOME = D:\app\Administrator\product\11.2.0\dbhome_1)
(SID_NAME = ORCL)
)
)
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
)
)
ADR_BASE_LISTENER = D:\app\Administrator
标红的部分是后添加的，ORCL为监听的实例名。