关于jsp页面的更新与查询!!!
在一张jsp页面中,要同时执行更新和查询两个操作,若单单查询,没有问题,如果我先进行更新,然后再查询,页面就无法显示(页面进度条缓慢进行,最终也没显示出来),也不提示任何错误!(但如果我直接在java类中的main函数进行更新和查询,缺没有任何问题).

各位大虾相助,都搞一个星期了~~555

以下是连接数据库的类:
-----------------------------------
package   com.matrix.mail;

import   java.sql.*;
import   java.util.Properties;
import   java.io.*;

public   class   DBConn
{
String   dbDriver= " ";
String   url= " ";
String   userName= " ";
String   password= " ";
//String   sDBDriver= "net.sourceforge.jtds.jdbc.Driver ";
//String   sConnStr= "jdbc:jtds:sqlserver://192.168.150.190:1433/guestbook ";
private   Connection   conn=null;
private   Statement   stmt=null;
ResultSet   rs=null;

public   DBConn()
{
InputStream   is   =   getClass().getResourceAsStream( "db.properties ");
Properties   dbProps   =   new   Properties();
try   {
dbProps.load(is);
}   catch   (Exception   e)   {
System.err.println( "Can 't   read   the   properties   file.   "
+   "Make   sure   db.properties   is   in   the   CLASSPATH ");
}
dbDriver=dbProps.getProperty( "dbDriver_jtds ");
url   =   dbProps.getProperty( "url_jtds ");
userName   =   dbProps.getProperty( "userName ");
password   =   dbProps.getProperty( "password ");

try
{//注册数据库驱动程序
Class.forName(dbDriver);
}
catch(java.lang.ClassNotFoundException   e)
{
System.err.println(e.getMessage());
}
}
//建立数据库连接及定义数据查询
public   ResultSet   executeQuery(String   sql)
{
rs=null;
try
{
//创建数据库联接对象
conn=DriverManager.getConnection(url,userName,password);
stmt=conn.createStatement();
rs=stmt.executeQuery(sql);
}
catch(SQLException   ex)
{
System.err.println( "aq.executeQuery: "+ex.getMessage());
}
return   rs;
}
//定义数据操作
public   void   executeUpdate(String   sql)
{
stmt=null;
rs=null;
try
{
conn=DriverManager.getConnection(url,userName,password);//创建数据库联接对象
stmt=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
stmt.executeUpdate(sql);
}
catch(SQLException   ee)
{
System.err.println( "aq.executeUpdate: "+ee.getMessage());
}
}
public   PreparedStatement   getPreparedStatement(String   sql)
{
PreparedStatement   ps=null;
try{
conn=DriverManager.getConnection(url,userName,password);
ps=conn.prepareStatement(sql);
return   ps;
}catch(SQLException   ee)
{
dispose(ps);
ee.printStackTrace();
return   null;
}
}
//关闭Statement
public   void   closeStmt()
{
try
{
stmt.close();
}
catch(SQLException &n