TNS-12541 TNS no listener

转载：https://blog.csdn.net/haha_201510/article/details/88119587

centOS环境下的解决方案：

查看监听状态lsnrctl status

如果有监听，则如下图，显示有服务orcl(服务名)监听。

如果没有监听，查看监听文件

cd /u01/app/oracle/product/11.2.0/db_1/network/admin

tnsnames.ora:用于客户端,提示客户端从哪个监听实例连接。

  LISTENER_ORCL =
     (ADDRESS = (PROTOCOL = TCP)(HOST = localhost.localdomain)(PORT = 1521))
   
   ORCL =
     (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = localhost.localdomain)(PORT = 1521))
      (CONNECT_DATA =
        (SERVER = DEDICATED)
        (SERVICE_NAME = orcl)
      )
    )

listener.ora：用于服务端，用于提示服务端监听哪些实例。

LISTENER =
     (DESCRIPTION_LIST =
       (DESCRIPTION =
         (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
         (ADDRESS = (PROTOCOL = TCP)(HOST =localhost.localdomain)(PORT = 1521))
   #      (ADDRESS = (PROTOCOL = TCP)(HOST =192.168.0.105)(PORT = 1521))
      )
    )
  SID_LIST_LISTENER =
    (SID_LIST =
      (SID_DESC =
        (GLOBAL_DBNAME = orcl)
        (ORACLE_HOME = /u01/app/oracle/product/11.2.0/db_1/)
        (SID_NAME = ORCL)
      )
    )
    #PS: 这里面的SID_NAME是oracle实例名，GLOBAL_DBNAME是全局的dbname，是db_unique_name
  
  LISTENER =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = localhost.localdomain)(PORT = 1521))
    )
  
  
  ADR_BASE_LISTENER = /u01/app/oracle

其中HOST为当前主机名（可以使用本机的IP地址）。

注意：当前我的hosts文件的配置如下

[root@192 etc]# vim /etc/hosts

  127.0.0.1   localhost localhost.localdomain                                 
  ::1         localhost localhost.localdomain