解决idea连接mysql连接失败Could not create connection to database server. Attempted reconnect 3 times. Giving up.

如下图

解决办法:

在URL后面添加参数即可：

?useUnicode=true&characterEncoding=UTF-8&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC