Oracle数据库通过监听器与客户端建立连接，监听器程序由一个Oracle文件进行管理，文件名为listener.ora,Linux系统下存放于$ORACL_HOME/network/admin目录下。监听器必须运行在Oracle数据库服务器上，数据库服务通过动态注册或静态注册两种方式注册到监听器程序后，客户端即可通过监听器访问对应的数据库。
一、监听器配置
如下为一段监听文件的配置，有配置可以LISTENER采用TCP协议，数据库地址为192.168.0.9，默认端口为1521。如要新增监听器，可以直接修改该文件添加。
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.0.9)(PORT = 1521))
)
)
ADR_BASE_LISTENER = /u01/app/oracle
监听器常用命令
Oralce使用lsnrct命令完成监听器程序的日常管理，常用命令有
lsnrctl status #查看监听器状态
lsnrctl start #启动监听器
lsnrctl stop #停止监听程序
二、动态注册
查看监听器状态：
[oracle@centos6 admin]$ lsnrctl status LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 11-SEP-2018 08:19:45 Copyright (c) 1991, 2009, Oracle. All rights reserved. Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=192.168.0.9)(PORT=1521))) STATUS of the LISTENER ------------------------ Alias LISTENER Version TNSLSNR for Linux: Version 11.2.0.1.0 - Production Start Date 11-SEP-2018 08:19:39 Uptime 0 days 0 hr. 0 min. 5 sec Trace Level off Security ON: Local OS Authentication SNMP OFF Listener Parameter File /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora Listener Log File /u01/app/oracle/diag/tnslsnr/centos6/listener/alert/log.xml Listening Endpoints Summary... (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.0.9)(PORT=1521))) The listener supports no services The command completed successfully
由上述信息可知监听器没有任何服务注册过来，可以通过修改local_listener参数让数据库动态注册到监听器上，例子如下：
SQL> alter system set 2 local_listener='(address_list=(address=(protocol=tcp)(host=192.168.0.9)(port=1521)))'; System altered.
改参数已经修改立即生效，此时查看系统中的local_listener指和监听器状态如下：
SQL> show parameter local_listener; NAME TYPE ------------------------------------ --------------------------------- VALUE ------------------------------ local_listener string (address_list=(address=(protoc ol=tcp)(host=192.168.0.9)(port =1521)))
[oracle@centos6 admin]$ lsnrctl status LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 11-SEP-2018 08:30:55 Copyright (c) 1991, 2009, Oracle. All rights reserved. Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=192.168.0.9)(PORT=1521))) STATUS of the LISTENER ------------------------ Alias LISTENER Version TNSLSNR for Linux: Version 11.2.0.1.0 - Production Start Date 11-SEP-2018 08:19:39 Uptime 0 days 0 hr. 11 min. 16 sec Trace Level off Security ON: Local OS Authentication SNMP OFF Listener Parameter File /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora Listener Log File /u01/app/oracle/diag/tnslsnr/centos6/listener/alert/log.xml Listening Endpoints Summary... (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.0.9)(PORT=1521))) Services Summary... Service "orcl" has 1 instance(s). Instance "orcl", status READY, has 1 handler(s) for this service... Service "orclXDB" has 1 instance(s). Instance "orcl", status READY, has 1 handler(s) for this service... The command completed successfully
由上述信息可知数据库服务已经注册过来了。
三、静态注册
先执行如下代码停止系统自动注册
SQL> alter system set 2 local_listener=''; System altered.
此时系统监听状态如下
[oracle@centos6 admin]$ lsnrctl status LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 11-SEP-2018 08:35:26 Copyright (c) 1991, 2009, Oracle. All rights reserved. Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=192.168.0.9)(PORT=1521))) STATUS of the LISTENER ------------------------ Alias LISTENER Version TNSLSNR for Linux: Version 11.2.0.1.0 - Production Start Date 11-SEP-2018 08:19:39 Uptime 0 days 0 hr. 15 min. 47 sec Trace Level off Security ON: Local OS Authentication SNMP OFF Listener Parameter File /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora Listener Log File /u01/app/oracle/diag/tnslsnr/centos6/listener/alert/log.xml Listening Endpoints Summary... (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.0.9)(PORT=1521))) The listener supports no services The command completed successfully
静态注册是间数据库信息直接写到监听器配置文件中，当监听器启动时就会自动注册数据库服务，达道静态注册的效果。需要注意的是，采用静态注册方式，在修改监听器配置文件后，需要重启监听器配置才能生效。具体配置参考如下例子:
[oracle@centos6 admin]$ cat listener.ora
# listener.ora Network Configuration File: /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora
# Generated by Oracle configuration tools.
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.0.9)(PORT = 1521))
)
)
SID_LIST_LISTENER=
(SID_LIST=
(SID_DESC=
(SID_NAME=orcl)
(ORACLE_HOME=/u01/app/oracle/product/11.2.0/dbhome_1)
(GLOBAL_DBNAME=orcl)
)
)
ADR_BASE_LISTENER = /u01/app/oracle
重启监听程序后，查看监听器状态：
[oracle@centos6 admin]$ lsnrctl stop LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 11-SEP-2018 08:39:34 Copyright (c) 1991, 2009, Oracle. All rights reserved. Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=192.168.0.9)(PORT=1521))) The command completed successfully [oracle@centos6 admin]$ lsnrctl start LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 11-SEP-2018 08:39:44 Copyright (c) 1991, 2009, Oracle. All rights reserved. Starting /u01/app/oracle/product/11.2.0/dbhome_1/bin/tnslsnr: please wait... TNSLSNR for Linux: Version 11.2.0.1.0 - Production System parameter file is /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora Log messages written to /u01/app/oracle/diag/tnslsnr/centos6/listener/alert/log.xml Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.0.9)(PORT=1521))) Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=192.168.0.9)(PORT=1521))) STATUS of the LISTENER ------------------------ Alias LISTENER Version TNSLSNR for Linux: Version 11.2.0.1.0 - Production Start Date 11-SEP-2018 08:39:44 Uptime 0 days 0 hr. 0 min. 0 sec Trace Level off Security ON: Local OS Authentication SNMP OFF Listener Parameter File /u01/app/oracle/product/11.2.0/dbhome_1/network/admin/listener.ora Listener Log File /u01/app/oracle/diag/tnslsnr/centos6/listener/alert/log.xml Listening Endpoints Summary... (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.0.9)(PORT=1521))) Services Summary... Service "orcl" has 1 instance(s). Instance "orcl", status UNKNOWN, has 1 handler(s) for this service... The command completed successfully
由上述信息可知，监听器已正常启动起来。