-0" java.lang.ClassCastException: org.apache.derby.client.net.NetConnection40 cannot be cast to com.mysql.jdbc.Connectionjava.awt.EventDispatchThread.run(EventDispatchThread.java:82)它说连接已完成=trueimport com.mys
java.lang.ClassCastException: com.mysql.jdbc.JDBC4ResultSet cannot be cast to com.mysql.jdbc.ResultSetcom.hotel.database;
import com.mysql.jdbc.PreparedStatement;
im