方案一：
1.停止mysql
service mysql stop
2.添加一下参数到mysql配置文件‘/usr/local/mysql/f’
--skip-grant-tables
3.启动mysql
service mysql start
4.执行一下命令进入mysql
mysql
5.更新密码注意这是mysql5.7的方式
mysql>update mysql.user set authentication_string=password('123456') where user='root' and Host ='localhost';
5.7之前的应该这样改：
update user set password=password("123") where user="root";
6.去掉配置文件添加的参数‘--skip-grant-tables’，重启mysql，就ok了
方案二：
参考：/article/77858.htm1[root@www.woai.it ~]# service mysql stop2[root@www.woai.it ~]# mysqld_safe --skip-grant-tables &3[root@www.woai.it ~]# mysqld_safe --skip-grant-tables --skip-networking &4[root@www.woai.it ~]# mysql -p5mysql> update mysql.user set authentication_string=password('123qwe') where user='root' and Host = 'localhost';6mysql> flush privileges;mysql> quit;7[root@localhost ~]# service mysql restart
