Java.sql.SQLException:null, message from server: "Host ' xxx ' isn't allowed to connect to this MySQL server"

Java.sql.SQLException:null, message from server: "Host ' xxx ' isn't allowed to connect to this MySQL server":

Indicates that the object is not a remote object and that the data cannot be accessed remotely through the object

Solve:

Plan One: Change the table:

Use MySQL, select User,host,password from user;

Update user Set host = '% ' where user= ' root ';

Programme II: Authorization Law:

For example, if you want to myuser use MyPassword to connect to a MySQL server from any host.
GRANT all privileges on * * to ' myuser ' @ ' percent ' identified by ' MyPassword ' with GRANT OPTION;
If you want to allow users to connect to the MySQL server from a host myuser IP 192.168.1.3 and use MyPassword as the password
GRANT all privileges on * * to ' myuser ' @ ' 192.168.1.3 ' identified by ' MyPassword ' with GRANT OPTION;

The MySQL database needs to be restarted.

Java.sql.SQLException:null, message from server: "Host ' xxx ' isn't allowed to connect to this MySQL server"