注意：云服务器安全组规则允许3306端口访问（防火墙允许3306端口访问）
*Host is not allowed to connect to this MySQL server**
使用root权限登入MySQL，更改"mysql"数据库里的"user"表里的"Host"字段，从"localhost"改为’%’
$ mysql -u root -p
>> use mysql;
>> select * from `user`;
>> update `db` set `Host` = '%' where `db`.`Host` = 'localhost' and `db`.`Db` = 'db-name' and `db`.`User` = 'db-user';
>> update `db` set `Host` = '%' where `db`.`Host` = 'localhost' and `db`.`Db` = 'db-name\\_%' and `db`.`User` = 'db-user';
>> update `user` set `Host` = '%' where `user`.`Host` = 'localhost' and `user`.`User` = 'db-user';
>> flush privileges;- db-user: 数据库用户名
Access denied for user ‘db-user’@’%’ to database ‘db-name’
grant all on db-name.* to 'db-user'@'%' identified by 'db-password' with grant option;- db-name: 数据库名称
- db-user: 数据库所属用户
- db-password: 数据库用户登录密码
