mysql连接数据库时出现Unknown character set index for field
来源：blog.csdn.net 编辑：xjh 2018-09-22
mysql8.0连接数据库时，出现Unknown character set index for field 255 received from server.
原因是：MySQL server版本高，mysql的jar版本低造成mysql与jar的编码错乱引起的，我的MYSQL是8.0版本。MYSQL 5.5 之前， UTF8 编码只支持1-3个字节;从MYSQL5.5开始，可支持4个字节UTF编码utf8mb4;
问题解决：更换jar包，升级lib目录下jar包:mysql-connector-java-5.1.47-bin.jar或者更高，根据mysql版本决定。
error log:
java.sql.SQLException: Unknown character set index for field 255 received from server.
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:910)
at com.mysql.jdbc.Connection.getCharsetNameForIndex(Connection.java:3396)
来源参考:
https://blog.csdn.net/qq_38674645/article/details/81105266