遇到错误：ORA-12514: TNS: 监听程序当前无法识别连接描述符中请求的服务

1，检查TNS服务，没问题，重启一下。

2，用助手重建监听，最好先删除，再重建。

3，如果还不行，修改listener.ora，问题可以解决，如下：

文件位置：D:/oracle/product/11.2.0/dbhome_1/NETWORK/ADMIN

整个文件内容如下，修改部分标明了。

# listener.ora Network Configuration File: d:/oracle/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:/oracle/product/11.2.0/dbhome_1)
      (PROGRAM = extproc)
      (ENVS = "EXTPROC_DLLS=ONLY:d:/oracle/product/11.2.0/dbhome_1/bin/oraclr11.dll")
    )
-------------修改部分原内容
    (SID_DESC =
      (SID_NAME = CLRExtProc)
      (ORACLE_HOME = d:/oracle/product/11.2.0/dbhome_1)
      (PROGRAM = extproc)
      (ENVS = "EXTPROC_DLLS=ONLY:d:/oracle/product/11.2.0/dbhome_1/bin/oraclr11.dll")
    )
-------------修改为
    (SID_DESC =
      (GLOBAL_DBNAME = orcl)
      (ORACLE_HOME = d:/oracle/product/11.2.0/dbhome_1)
      (SID_NAME = orcl)     
    )
-------------
  )

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = SVR-HSDB)(PORT = 1521))
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
    )
  )

ADR_BASE_LISTENER = d:oracle

再次连接，OK。