could not get JDBC Connection； nested exception is java.sql.SQLException: Unknown initial character的

could not get JDBC Connection; nested exception is java.sql.SQLException: Unknown initial character set index ‘255’ received from server. Initial client character set can be forced via the ‘characterEncoding’ property.

这个问题原因是配置jdbc.properties的文件内容出错了，其中的编码格式没有得到统一，我们需要在jdbc链接中增加对编码格式characterEncoding的规定。

解决方法：jdbc:mysql://localhost:3306/数据库名?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai