为什么它总是提示连接数据库失败!??
description The server encountered an internal error (Internal Server Error) that prevented it from fulfilling this request.exception java.lang.NullPointerException
at demo.DataBaseConn.executeQuery(DataBaseConn.java:49)
at org.apache.jsp.selectExample$jsp._jspService(selectExample$jsp.java:104)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:107)