IDEA报错
ERROR 18800 --- [ task-1] com.zaxxer.hikari.pool.HikariPool : HikariPool-1 - Exception during pool initialization.

提示
Loading class 'com.mysql.jdbc.Driver'. This is deprecated. The new driver class is 'com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.
应该将'com.mysql.jdbc.Driver'替换为新的驱动类'com.mysql.cj.jdbc.Driver'

java.sql.SQLException: The server time zone value '�й���׼ʱ��' 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.

Caused by: com.mysql.cj.exceptions.InvalidConnectionAttributeException: The server time zone value '�й���׼ʱ��' 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. at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
这里提示zone vlause 乱码
那么修改url设置如下
url = jdbc:mysql://localhost:3306/examonline?serverTimezone=UTC&useSSL=false

最后的配置就是

driverClass = com.mysql.cj.jdbc.Driver
url = jdbc:mysql://localhost:3306/examonline?serverTimezone=UTC&useSSL=false

springboot启动成功