异常错误：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.
这个问题是 使用了新的mysql驱动包，但驱动声明不是最新的：
DriverClassName 从 "com.mysql.jdbc.Driver" 换成 "com.mysql.cj.jdbc.Driver" 即可