oracle 12c Enterprise Manager Database Express

-- 一句话说的很明白：
you've probably already got EM Database Express configured. Unlike the DB Control, it runs from inside the database using the XML DB infrastructure,
so there are no additional parts to install or executables to start.If your organisation uses Cloud Control, which it should, you will probably never use
EM Database Express. If on the other hand you are playing around with the database and want a pretty interface to perform some tasks,
the EM Database Express might be your answer
--启用：
SQL> exec dbms_xdb_config.sethttpsport(5501);

PL/SQL 过程已成功完成。

SQL> exec dbms_xdb_config.sethttpport(5502);

PL/SQL 过程已成功完成。

如果想--禁用：
SQL> exec dbms_xdb_config.sethttpsport(0);

PL/SQL 过程已成功完成。

-- 查看
SQL> SELECT DBMS_XDB_CONFIG.gethttpport FROM dual;

GETHTTPPORT
-----------
0

SQL> SELECT DBMS_XDB_CONFIG.gethttpsport FROM dual;

GETHTTPSPORT
------------
5500