problem JSP code following:
<%
... ...
Statement stmt = connection.createStatement();
ResultSet rs =
  stmt.executeQuery("select prod_id, weight from product");
String prod_id = "";
float weight = 0;
while (rs.next()){
  product_code = rs.getString("product_code");
  weight = rs.getFloat("weight");
}
stmt.close();
%>
jsp run error show:
java.sql.SQLException: [Microsoft][ODBC SQL Server Driver]invalid descriptors index
at sun.jdbc.odbc.JdbcOdbc.createSQLException(JdbcOdbc.java:6031)
at sun.jdbc.odbc.JdbcOdbc.standardError(JdbcOdbc.java:6188)
at sun.jdbc.odbc.JdbcOdbc.SQLGetDataFloat(JdbcOdbc.java:3097)
at sun.jdbc.odbc.JdbcOdbcResultSet.getDataFloat(JdbcOdbcResultSet.java:5285)
at sun.jdbc.odbc.JdbcOdbcResultSet.getFloat(JdbcOdbcResultSet.java:648)
... ...
But when i copied the problem code to a Java program, it run ok.
I don't know why and hope to get your comments!
Thanks

Luke

Accidentally i found the reason.
The order of getParameter must consistent with the select sentence.For example:

strSql = "select prod_id, name from product";
... ...
// OK
String prod_id = rs.getParameter("prod_id");
String name = rs.getParameter("name");

// Wrong
// error "invalid descriptor index" occur when running
String name = rs.getParameter("name");
String prod_id = rs.getParameter("prod_id");

strange!!!

This happens when u r trying to access the columns in a different sequence ie. if the column name n the value u r getting is not matching.
Ex:
column names
1:name 2:password 3:type
While retrieving it strictly retrive in the same sequence.
 
If u r using MS-Access it works but DBs like MS-SQL wont work.
 Hope this helps.

Thank you for the solution. It really solved my problem that i have tried for two days. thanks again.