Caused by: java.sql.SQLException: Incorrect string value: 'xF6x9Dx98x84' for column 'comment' at row 1

[client]
default-character-set=utf8mb4
 
[mysql]
default-character-set=utf8mb4
 
[mysqld]
character-set-server = utf8mb4
collation-server = utf8mb4_unicode_ci
init_connect = 'SET NAMES utf8mb4'
character-set-client-handshake = false

ALTER DATABASE post CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
 
ALTER TABLE `post_article` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
 
ALTER TABLE `post_article` MODIFY COLUMN `content` text CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

sudo /etc/init.d/mysql restart

SHOW VARIABLES WHERE Variable_name LIKE 'character%' OR Variable_name LIKE 'collation%';