我遇到了可怕的MySQLJDBC过时连接异常:Causedby:com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException:Nooperationsallowedafterconnectionclosed.Causedby:com.mysql.jdbc.exceptions.jdbc4.CommunicationsException:Thelastpacketsuccessfullyreceivedfromtheserverwas243,263,541millisecondsago.Thelastpacket