JDBC Link MySQL displays question mark after inserting data

1. In cmd, go to MySQL to view the default encoding format:
Mysql> Show variables like "%char%";

If it's not UTF8 (because I'm using UTF8), turn off the MySQL service and add it in My.ini

[Client]
Default-character-set=utf8

[Mysqld]
Default-storage-engine=innodb
Character-set-server=utf8
Collation-server=utf8_general_ci

[MySQL]
Default-character-set=utf8

Whether the encoding format in 2.eclipse is UTF8

3. If it is still not possible, check the MySQL client table encoding method

Show CREATE TABLE TableName

If it's not utf-8. Delete to re-create a table (previously I changed on the original table did not succeed, may be my own operation reasons)

JDBC Link MySQL displays question mark after inserting data