1、停止 mysql 服务

service mysqld stop 停止 mysql 服务

2、修改 mysql 服务启动配置 /etc/my.cnf

vi /etc/my.cnf 修改 my.cnf 文件 添加一行 skip-grant-tables

"/etc/my.cnf" 31L, 1261C written
# For advice on how to change settings please see
# http://dev.mysql.com/doc/refman/8.0/en/server-configuration-defaults.html

[mysqld]
skip-grant-tables  
# Remove leading # and set to the amount of RAM for the most important data
# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
# innodb_buffer_pool_size = 128M
#
# Remove the leading "# " to disable binary logging
# Binary logging captures changes between backups and is enabled by
# default. It's default setting is log_bin=binlog
# disable_log_bin
#
# Remove leading # to set options mainly useful for reporting servers.
# The server defaults are faster for transactions and fast SELECTs.
# Adjust sizes as needed, experiment to find the optimal values.
# join_buffer_size = 128M
# sort_buffer_size = 2M
# read_rnd_buffer_size = 2M
#
# Remove leading # to revert to previous value for default_authentication_plugin,
# this will increase compatibility with older clients. For background, see:
# https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html#sysvar_default_authentication_plugin
# default-authentication-plugin=mysql_native_password

datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock

log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

按 esc键 输入 :wq 保存退出

3、重启 mysql 服务

service mysqld restart

4、进入 mysql 清空密码

登陆mysql:    mysql -u root 

切换至权限数据库：use mysql；

清空密码：update user set authentication_string='' where user='root';

退出mysql：exit；

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5、重复 2、3步，不同的是 2是添加 skip-grant-tables，这里是 移除屏蔽的代码 skip-grant-tables，重启mysql 服务 使 my.cnf 文件生效

6、修改密码

进入mysql：mysql -u root -p 

提示需要输入密码的时候直接回车即可（上面已经将密码清空）

进入mysql后，切换数据库至mysql：use mysql;

设置密码：ALTER USER 'root'@'%' IDENTIFIED BY '新密码' ;

让密码马上生效：FLUSH PRIVILEGES;

使用navicat测试一下新密码，ok了。

20181105170118154.png