vim /etc/my.cnf文件；
在[mysqld]后添加skip-grant-tables（登录时跳过权限检查）
重启MySQL服务：sudo systemctl restart mysqld
登录mysql，输入mysql --uroot --p；直接回车（Enter）
输入：set password for 'root'@'localhost'=password('admin');
如果报：ERROR 1290 (HY000): The MySQL server is running with the --skip-grant-tables option so it cannot execute this statement
输入：flush privileges;
再次输入：set password for 'root'@'localhost'=password('Admin123@qwe');
为避免麻烦，再次设置远程访问
GRANT ALL PRIVILEGES ON *.* TO 'root'@'%'IDENTIFIED BY 'Admin123@qwe' WITH GRANT OPTION;
flush privileges;
退出：exit
再把my.ini的skip-grant-tables删除或者注释掉
重启MySQL：sudo systemctl restart mysqld
