com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Communications link failure during rollback(). Transaction resolution unknownx

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Communications link failure during rollback(). Transaction resolution unknown
最近上线了个小程序在线考试的功能，考试的人一多，后台就疯狂报这个错误。有遇到过的么

目测是连接池回收有问题，参考https://blog.csdn.net/liaojianqiu0115/article/details/89399185