解决 ERROR 1045 (28000): Access denied for user '...

最近新装好的mysql在进入mysql工具时，总是有错误提示:

mysql -u root -p

Enter password:
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)
或者

mysql -u root -p password 'newpassword'

Enter password:
mysqladmin: connect to server at 'localhost' failed
error: 'Access denied for user 'root'@'localhost' (using password: YES)'

现在终于找到解决方法了。本来准备重装的，现在不必了。
方法操作很简单，如下：

/etc/init.d/mysql stop

mysqld_safe –user=mysql –skip-grant-tables –skip-networking &

mysql -u root mysql

mysql> UPDATE user SET Password=PASSWORD('newpassword') where USER='root' and host='root' or host='localhost';//把空的用户密码都修改成非空的密码就行了。
mysql> FLUSH PRIVILEGES;
mysql> quit # /etc/init.d/mysqld restart

mysql -uroot -p

Enter password: <输入新设的密码newpassword>