java.sql.SQLException: Unknown initial character set index '255' received from server. Ini

描述：java项目连Mysql时报错“java.sql.SQLException: Unknown character set index for field ‘255‘ received from server”

原因：这是编码不匹配的原因，mysql驱动和数据库字符集设置不搭配，默认字符集已从latin1变成utf8mb4，因而系统变量受到影响

解决：直接在连接的URL后加上

useUnicode=true&characterEncoding=utf8

就可以了。

或者直接升级jar包！！

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

原文地址：https://www.cnblogs.com/xuyupengblogs/p/12951538.html