A twist on only getting 20 records at a time

Question

Hi,
Goal:
Generate a search-engine like result page which displays 20 records at a time. Clicking "Next" will permit viewing the next 20 records, and so on.
Current code:
A JSP page posts a form to a servlet which, based on form selections, dynamically builds a SQL statement, which in turn is passed to a Bean which queries the DB and returns ALL records. Works great, but returns too much data for a web page (JSP).
Problem:
I have posted on the JSP forum, and have only been pointed to sites offering Custom JSP Tags which either query all records at once and only show you X at a time, (which I consider inefficient) or place the JDBC/SQL code in the JSP page, which I don't like either. So....
Question:
How do I achieve this? I have tried playing with the getMaxRoxs() and setFetchSize() methods to no avail. I am relatively new to this, but I think it has a lot to do with how JSP pages instantiate Beans (I.E: Every time the page loads, the bean is instantiated and all records are returned).
Any help is greatly appreciated! I have tried so many things and searched the web, but have not found any concrete examples with code.
- J

Answer 1

My proposal was smth like this:
ArrayList myData = new ArrayList();
while (rSet.next()) {
    MyObjType myObj = new MyObjType(...);
    int i = 0;
    myObj.setAttribute1(rSet.getXXX(++i)); // getXXX is the proper method for the type of myObj.attribute1
    myObj.setAttribute2(rSet.getXXX(++i)); // getXXX is the proper method for the type of myObj.attribute2
    myObj.setAttributen(rSet.getXXX(++i)); // getXXX is the proper method for the type of myObj.attributen
    myData.add(myObj);
session.setAttribute("myData", myData);
...Here MyObjType is the type (class) designed by you to hold one record of your result set. Example:
For the
TABLE BOOK
ID NUMBER(10)
TITLE CHAR(30)
PRICE DECIMAL(2, 12)
AUTHOR_ID NUMBER(10)
Your MyObjType class will be probably named Book and will look like this:
public class Book {
    private long id = -1;
    private String title = null;
    private double price = Double.NaN;
    private long authorId = -1;
    public long getId() {
        return this.id;
    public void setId(long id) {
        this.id = id;
    public long getAuthorId() {
        return this.authorId;
    public void setAuthorId(long authorId) {
        this.authorId = authorId;
    public String getTitle() {
        return this.title;
    public void setTitle(String title) {
        this.title = title;
    public double getPrice() {
        return this.price;
    public void setId(double price) {
        this.price = price;
}So, you have an ArrayList of Book objects stored in your session object. Now you receive a request like this:
gimmemydata?rowsfrom=20&rowsto=40
Your JSP does just:
<%
ArrayList myData = (ArrayList) session.getAttribute("myData");
int rowsFrom = -1;
int rowsTo = -1;
try {
    rowsFrom = Integer.parseInt(request.getParameter("rowsfrom"));
    rowsTo = Integer.parseInt(request.getParameter("rowsto"));
catch (Exception ex) {;}
if (rowsFrom < 0 || rowsTo < 0) {
    rowsFrom = 0;
    rowsTo = 20;
%>
<table>
<%
for (int i = rowsFrom; i < rowsTo; i++) {
    Book book = (Book) myData.get(i);
%>
<tr>
  <td><%= book.getTitle() %></td>
  <td align="right"><%= book.getPrice %></td>
</tr>
<%
%>
</table>
...It is as easy as that...
Sorry, the closing brackets of the tags look a bit funny :-)