os: centos 7.6
db: oracle 19.3
Enterprise Manager Database Control is no longer available in Oracle Database 12c.
You can use Enterprise Manager Cloud Control 12c or EM Express 12c to manage your Oracle Database 12c databases.
Enterprise Manager Cloud Control supports Oracle Database 12c targets, including multitenant container databases (CDBs), pluggable databases (PDBs), non-CDBs, Oracle Real Application Clusters (Oracle RAC) databases, and Oracle Automatic Storage Management (Oracle ASM) databases.
EM Express is a servlet built on top of Oracle XML DB. The Oracle XML DB default wallet has a self-signed certificate, and some existing browsers consider self-signed certificates as untrusted because they are not signed by a trusted CA (certificate authority). However, the self-signed certificate is still secure, as it ensures that the traffic is encrypted between the Oracle XML DB server and the client (browser).
SQL> show parameter local_listener;
show parameter dispatchers;
SQL> select dbms_xdb_config.getHttpsPort() from dual;
select dbms_xdb_config.getHttpPort() from dual;
SQL> exec DBMS_XDB_CONFIG.SETGLOBALPORTENABLED(TRUE);
exec dbms_xdb_config.sethttpsport(5500);
exec dbms_xdb_config.sethttpport(8080);
$ lsnrctl status | grep HTTP
通过URL访问
https://node1:5500/em
http://node1:8080/em
可以对需要登录的用户授权
SQL> grant EM_EXPRESS_BASIC to <user>;
grant EM_EXPRESS_ALL to <user>;
停止 EM Database Express
SQL> exec dbms_xdb_config.sethttpsport(0);
exec dbms_xdb_config.sethttpport(0);
to Flash Oracle EM Express :
SQL> @?/rdbms/admin/execemx emx
to JET Oracle EM Express :
SQL> @?/rdbms/admin/execemx omx
参考：
https://www.oracle.com/technetwork/database/manageability/emx-intro-1965965.html
https://docs.oracle.com/en/database/oracle/oracle-database/19/multi/creating-and-configuring-a-cdb.html#GUID-21DEC1B3-471C-4220-A0F6-6780E6DC6009
https://docs.oracle.com/en/database/oracle/oracle-database/19/admqs/getting-started-with-database-administration.html#GUID-BA75AD46-D22E-4914-A31E-C395CD6A2BBA