The server time zone value '???ú±ê×??±??' is unrecognized or represents more than one time zone.

报错内容：

com.mysql.cj.exceptions.InvalidConnectionAttributeException:The server time zone value '???ú±ê×??±??' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support.

分析：数据库时区设置错误。

解决方法：分两种，但原理都是时区设置为当前系统时区

1、在连接数据库语句中的url变量中修改

Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/t_user","root","root");//修改前
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/t_user?serverTimezone=GMT%2B8","root","root");//修改后

2、使用root用户登录mysql，执行以下语句

set global time_zone='+8:00';

提示Query OK...即为成功。