Unknown initial character set index '255' received from server

刚学mybatis，测试的时候有异常：

Caused by: java.sql.SQLException: Unknown initial character set index '255' received from server. 
Initial client character set can be forced via the 'characterEncoding' property.

去检查数据库的数据，有汉字

 

就在url后面加上了"?characterEncoding=utf8"之后就可以正常显示了。