首先查看服务端字符集

select * from v$nls_parameters where parameter = 'NLS_CHARACTERSET'

NLS_CHARACTERSET WE8MSWIN1252

然后用sys用户进行修改

sqlplus "/as sysdba"

shutdown immediate;
startup mount;
ALTER SESSION SET SQL_TRACE=TRUE;
ALTER SYSTEM ENABLE RESTRICTED SESSION;
ALTER SYSTEM SET JOB_QUEUE_PROCESSES=0;
ALTER SYSTEM SET AQ_TM_PROCESSES=0;
ALTER DATABASE OPEN;
alter database character set AL32UTF8;

ORA-12712: new character set must be a superset of old character set
RROR at line 1:

结果报错，提示新字符集必须是老字符集的超集。

于是强制转换

ALTER DATABASE character set INTERNAL_USE AL32UTF8;

shutdown immediate;

STARTUP;

问题解决。