1. 关掉mysql服务，打开系统设置最后的mysql,然后将mysql先关掉

2. 生成一个文件命名mysql-init，文件中放入：一句话，这句话不同版本不一样，如下：（括号里面不包含）

alter user ‘root’@‘localhost’ identified by ‘新密码’；(MySQL 5.7.6 and later)

set password for ‘root’@‘localhost’=password(‘新密码’);(MySQL 5.7.5 and earlier)

3. cd /usr/local/mysql/bin/

sudo su

mysqld_safe —init-file=/home/me/mysql-init &

mysqld_safe —skip-grant-tables &

./mysql

flush privileges;

update mysql.user  set authentication_string = password(‘你在文件中定义的新密码’)，password_expired = ’N’ where user = ‘root’ and host = ‘localhost’;

flush privileges;

quit;

./mysql -u root -p

输入你的新密码就好了

参考：B.5.3.2.2 Resetting the Root Password: Unix and Unix-Like Systems小节(http://dev.mysql.com/doc/refman/5.7/en/resetting-permissions.html)