直接修改数据库:

use DATABASE;
delete from ofuser where username='admin';
INSERT INTO ofUser (username, plainPassword, name, email, creationDate, modificationDate) VALUES ('admin', 'admin', 'Administrator', 'admin@example.com', '0', '0');
# 或
update ofUser set plainPassword='newpassword', encryptedPassword=null where username='admin';
flush privileges;

修改之后,重启openfire,使用 admin/admin登录,登录后修改admin密码。