高版本改法
<dependency>
  <groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
  <version>8.0.20</version>
</dependency>

把com.mysql.jdbc.Driver改成com.mysql.cj.jdbc.Driver

把jdbc:mysql://localhost:3306/smbms?useSSL=true&useUnicode=true&characterEncoding=UTF-8改成jdbc:mysql://localhost:3306/test?useSSL=true&useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC

使用com.mysql.cj.jdbc.Driver需要指定时区serverTimezone