当出现下面错误时：

mysqldump: Got error: 1449: The user specified as a definer ('root'@'%') does not exist when using LOCK TABLES

是权限问题，解决办法，执行两条SQL语句就好：

grant all privileges on *.* to root@"%" identified by ".";
flush privileges;

在命令中执行图：

mysql> grant all privileges on *.* to root@"%" identified by ".";
Query OK, 0 rows affected (0.00 sec)
 
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)