创建表空间和用户时，需要的时候竟然忘记了密码，试了好多次都没连接上，进而用户也被锁定，下面就教您处理Oracle默认用户的密码问题的方法，希望对和我一样情况的朋友们有所帮助。
1.安装时选择的自动安装，忘了用户名和密码导致现在试了几个Oracle默认用户名密码后（表格中附带默认用户名及密码），都提示无效的用户名、密码，
Username
Password
Description
See Also
CTXSYS
CTXSYS
The Oracle Text account
Oracle Text Reference
DBSNMP
DBSNMP
The account used by the Management Agent component of Oracle Enterprise Manager to monitor and manage the database
Oracle Enterprise Manager Grid Control Installation and Basic Configuration
LBACSYS
LBACSYS
The Oracle Label Security administrator account
Oracle Label Security Administrator's Guide
MDDATA
MDDATA
The schema used by Oracle Spatial for storing Geocoder and router data
Oracle Spatial User's Guide and Reference
MDSYS
MDSYS
The Oracle Spatial and Oracle interMedia Locator administrator account
Oracle Spatial User's Guide and Reference
DMSYS
DMSYS
The Oracle Data Mining account.
Oracle Data Mining Administrator's Guide
Oracle Data Mining Concepts
OLAPSYS
MANAGER
The account used to create OLAP metadata structures. It owns the OLAP Catalog (CWMLite).
Oracle OLAP Application Developer's Guide
ORDPLUGINS
ORDPLUGINS
The Oracle interMedia user. Plug-ins supplied by Oracle and third party format plug-ins are installed in this schema.
Oracle interMedia User's Guide
ORDSYS
ORDSYS
The Oracle interMedia administrator account
Oracle interMedia User's Guide
OUTLN
OUTLN
The account that supports plan stability. Plan stability enables you to maintain the same execution plans for the same SQL statements. OUTLN acts as a role to centrally manage metadata associated with stored outlines.
Oracle Database Performance Tuning Guide
SI_INFORMTN_SCHEMA
SI_INFORMTN_SCHEMA
The account that stores the information views for the SQL/MM Still Image Standard
Oracle interMedia User's Guide
SYS
CHANGE_ON_INSTALL
The account used to perform database administration tasks
Oracle Database Administrator's Guide
SYSMAN
CHANGE_ON_INSTALL
The account used to perform Oracle Enterprise Manager database administration tasks. Note that SYS and SYSTEM can also perform these tasks.
Oracle Enterprise Manager Grid Control Installation and Basic Configuration
SYSTEM
MANAGER
Another account used to perform database administration tasks.
Oracle Database Administrator's Guide
这时候要找到一组用户名、密码提示被锁，才能进行下一步
安装ORACLE时，若没有为下列用户重设密码，则其默认密码如下：
用户名/密码
登录身份
说明
sys/change_on_install
SYSDBA或SYSOPER
不能以NORMAL登录，可作为默认的系统管理员
system/manager
SYSDBA或NORMAL
不能以SYSOPER登录，可作为默认的系统管理员
sysman/oem_temp
sysman 为oms的用户名
scott/tiger
NORMAL
普通用户
aqadm /aqadm
SYSDBA或NORMAL
高级队列管理员
Dbsnmp/dbsnmp
SYSDBA或NORMAL
复制管理员
2.在CMD中启动SQLPLUS；用sqlplus/as sysdba登录，提示
连接到:
Oracle Database 10g Express Edition Release 10.2.0.1.0 - Production
3. 执行ALTER USER 你被锁的用户名 ACCOUNT UNLOCK；
4. 重新用SQL/PLUS登录，用你刚刚解锁的用户名、密码；
重新修改密码就可以了！
具体操作如下：
1.运行->sqlplus /nolog
2.输入conn / as sysdba 管理员账户登录
3.如果用户被锁定先解锁：
alter user system account unlock;
4.修改密码：
alter user system identified by wanglj;
接下来可以用sqlplus登陆了。