当你的数据库版本是8版本的,而maven引入的是5版本的依赖就会出现java.math.BigInteger cannot be cast to java.lang.Long错误
引入8版本mysqlmaven依赖即可
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.20</version>
</dependency>