1.vi /etc/my.cnf

        [mysqld]段落中加上一句：skip-grant-tables保存并退出

2.重启mysql：service mysqld restart

3.进入mysql：mysql -u root

        update user set authentication_string='' where user='root';并退出

4.vi /etc/my.cnf

        [mysqld]段落中注释：skip-grant-tables保存并退出

5.重启mysql：service mysqld restart

6.再次进入mysql：mysql -u root

        6.1.use mysql;

        6.2.设置较复杂的新密码：ALTER USER 'root'@'%' IDENTIFIED WITH mysql_native_password BY '新密码';

        6.3.FLUSH PRIVILEGES;