停止 mysqld进程守护

systemctl stop mysqld.service

使用安全模式启动mysqld

mysqld_safe --skip-grant-tables --skip-networking

连接mysql并修改密码

mysql 

ALTER USER 'root'@'localhost' IDENTIFIED WITH 'mysql_native_password' BY '新密码';

// 刷新权限
FLUSH PRIVILEGES;

退出安全模式并重启进程守护

systemctl start mysqld.service

再次登录进行测试

mysql -u root -p