I want to create a JSP Form page (first.jsp) on Tomcat 4.1.27 with a
form that has about 20 input entries where the form will validate all
20 fields and show validation errors on the same page as the original
form page (first.jsp). For example, if someone has a blank entry on
the Firstname field then it will show this message in red next to the
field: First Name is required.

If the data passes the validations it will populate an Oracle
database.

Please advise any suggestions on how I should do this.

I was thinking of submitting the fields to a Controller servlet then
use the Enumeration class to get all field values where I would check
for blanks and valid email address. I assume I would not use a bean
and have a getter and setter method for all 20 fields?

//  Servlet controller part:
// Get the values of all request parameters
       Enumeration enum = req.getParameterNames();
       for (int i; enum.hasMoreElements();i++ )
       {
           /*
           put in ArrayList and
           validate and if not passing validation then pass it down
to next part
           */
       }
....
//next part - take value/s that dont pass and put in session variable
and redirect back to JSP

I dont have Struts and need to know the best way to do this.
Can anyone give me more example or ideas on this?