sql读取为空(急啊)

这是我的代码,数据库字段都是varchar类型,只能读取Member_Seller到Member_Email,其他的都读取不了.哪位高手解答一下.感激不尽!
<%@ page contentType="text/html; charset=gb2312" language="java" import="java.sql.*" errorPage="" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<jsp:useBean id="db" scope="page" class="wustbookbank.db.ConnectDB"/>
<jsp:useBean id="changeCode" scope="page" class="changeCode.ChangeCode"/>
<%
if(session.getAttribute("username")==null){
response.sendRedirect("../member/login.jsp?url="+request.getRequestURI());
}
%>
<%!
String logname,seller,problem,answer,email,realname,type,grade,address,city,postAdd,tel,sex,mobilephone,qq,selfintro,time;
%>
<%
String logname=(String)session.getAttribute("username");
String sql;
ResultSet rs;sql="select * from member where Member_ID='"+logname+"'";
rs=db.executeQuery(sql);
try{
   while(rs.next()){
   seller=rs.getString("Member_Seller");
   problem=rs.getString("Member_Question");
   answer=rs.getString("Member_Answer");
   email=rs.getString("Member_Email");
   realname=rs.getString("Member_Name");
   type=rs.getString("Member_Type");
   grade=rs.getString("Member_Grade");
   address=rs.getString("Member_Address");
   city=rs.getString("Member_City");
   postAdd=rs.getString("Member_Pc");
   tel=rs.getString("Member_Tel");
   sex=rs.getString("Member_Sex");
   mobilephone=rs.getString("Member_MobTel");
   qq=rs.getString("Member_QQ");
   selfintro=rs.getString("Member_Re");
   time=rs.getString("Member_RegTime");
   }
}catch(Exception e){
  }
   //判断是否为空，空则以无代替
   if(realname==null||realname.equals(""))realname="无";
   if(address==null||address.equals(""))address="无";
   if(city==null||city.equals(""))city="无";
   if(postAdd==null||postAdd.equals(""))postAdd="无";
   if(tel==null||tel.equals(""))tel="无";
   if(mobilephone==null||mobilephone.equals(""))mobilephone="无";
   if(qq==null||qq.equals(""))qq="无";
   if(selfintro==null||selfintro.equals(""))selfintro="无";
%>