Database Driven Dynamic pages

Question

Hi all,
I am new to jsp/servlets but I know java. I have been teaching myself jsp for a few weeks now, but i am unclear about a few things. I figure a good exercise would be to make a ecom. website for someone i know, which would help me learn and they would get a site for free. I am just unclear on creating the dynamic pages. Say i have 6 categories. I would like to click on the link and select all the products from that category and display them in a table on the page. I know you need to create a servelet that will query the db then you can create the table adding in the data from the DB and send it back to the client side. Im just not sure what its the best way to do this. I have seen code the looks like product?productCode=123131. and i believe this calls a servelet and passes in the 123131 as a parameter. I have a pretty good idea of how to do this but i am looking for an example or some kind of tutorial to help me along. I have been searching for a while and came up with nothing. I have been using this book while teaching myself.
Murach's Java Servlets and JSP
They have a pretty good example of an entire site but i am just getting stuck in this spot.
TIA
John

Answer 1

Sorry i was in rich text mode
web.xml
<servlet>
        <servlet-name>DisplayProducts</servlet-name>
        <servlet-class>category.DisplayProducts</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>DisplayProducts</servlet-name>
        <url-pattern>/product</url-pattern>
    </servlet-mapping>Product.java
package ecom;
     import java.text.NumberFormat;
     import java.io.Serializable;
     public class Product implements Serializable
          private int code;
          private String style;
          private String description;
          private double price;
          private String color;
          private String size;
          private String thumb;
          private String full;
          public Product()
               code = 0;
               style = "";
               description = "";
               price = 0;
               color = "";
               size = "";
               thumb = "";
               full = "";
          public void setCode(int code)
               this.code = code;
          public int getCode()
               return code;
          public String getStyle() {
               return style;
          public void setStyle(String style) {
               this.style = style;
          public void setDescription(String description)
               this.description = description;
          public String getDescription()
               return description;
          public void setPrice(double price)
               this.price = price;
          public double getPrice()
               return price;
          public String getColor() {
               return color;
          public void setColor(String color) {
               this.color = color;
          public String getSize() {
               return size;
          public void setSize(String size) {
               this.size = size;
          public String getThumb() {
               String imageURL = "/images/" + thumb;
               return imageURL;
          public void setThumb(String thumb) {
               this.thumb = thumb;
          public String getFull() {
               String imageURL = "/images/" + full;
               return imageURL;
          public void setFull(String full) {
               this.full = full;
          public String getPriceCurrencyFormat()
               NumberFormat currency = NumberFormat.getCurrencyInstance();
               return currency.format(price);
     }ProductDB.java
package data;
import java.sql.*;
import java.util.*;
import ecom.Product;
public class ProductDB {
    //This method returns null if a product isn't found.
    public static Product selectProduct(int productID)
        ConnectionPool pool = ConnectionPool.getInstance();
        Connection connection = pool.getConnection();
        PreparedStatement ps = null;
        ResultSet rs = null;
        String query = "SELECT A.PROD_SKU_ID, B.STYLE, B.DESCRIPTION, B.PRICE, A.COLOR, A.SIZE, C.THUMB_IMAGE, C.FULL_IMAGE "+
        "FROM TB_PRODUCT_SKU A "+
        "JOIN TB_PRODUCT B ON(A.PRODUCT_ID = B.PRODUCT_ID) "+
        "JOIN TB_WEB_IMAGE C ON(C.WEB_IMAGE_ID = B.WEB_IMAGE_ID) "+
        "WHERE A.PROD_SKU_ID = ? AND A.QUANTITY > 0";
        try
            ps = connection.prepareStatement(query);
            ps.setInt(1, productID);
            rs = ps.executeQuery();
            if (rs.next())
                Product p = new Product();
                 p.setCode(rs.getInt("PROD_SKU_ID"));
                   p.setStyle(rs.getString("STYLE"));
                   p.setDescription(rs.getString("DESCRIPTION"));
                   p.setPrice(rs.getDouble("PRICE"));
                   p.setColor(rs.getString("COLOR"));
                   p.setSize(rs.getString("SIZE"));
                   p.setThumb(rs.getString("THUMB_IMAGE"));
                   p.setFull(rs.getString("FULL_IMAGE"));
                return p;
            else
                return null;
        catch(SQLException e)
            e.printStackTrace();
            return null;
        finally
             UtilDB.closeResultSet(rs);
             UtilDB.closePreparedStatement(ps);
            pool.freeConnection(connection);
    //This method returns null if a product isn't found.
    public static ArrayList<Product> selectProducts(String cat_id)
         ConnectionPool pool = ConnectionPool.getInstance();
         Connection connection = pool.getConnection();
         PreparedStatement ps = null;
         ResultSet rs = null;
         String query = "SELECT A.PROD_SKU_ID, B.STYLE, B.DESCRIPTION, B.PRICE, A.COLOR, A.SIZE, C.THUMB_IMAGE, C.FULL_IMAGE "+
                        "FROM TB_PRODUCT_SKU A "+
                        "JOIN TB_PRODUCT B ON(A.PRODUCT_ID = B.PRODUCT_ID) "+
                        "JOIN TB_WEB_IMAGE C ON(C.WEB_IMAGE_ID = B.WEB_IMAGE_ID) "+
                        "WHERE CATEGORY_ID = " +cat_id+ "AND A.QUANTITY > 0";
         try
              ps = connection.prepareStatement(query);
              rs = ps.executeQuery();
              ArrayList<Product> products = new ArrayList<Product>();
              while (rs.next())
                   Product p = new Product();
                   p.setCode(rs.getInt("PROD_SKU_ID"));
                   p.setStyle(rs.getString("STYLE"));
                   p.setDescription(rs.getString("DESCRIPTION"));
                   p.setPrice(rs.getDouble("PRICE"));
                   p.setColor(rs.getString("COLOR"));
                   p.setSize(rs.getString("SIZE"));
                   p.setThumb(rs.getString("THUMB_IMAGE"));
                   p.setFull(rs.getString("FULL_IMAGE"));
                   products.add(p);
              return products;
         catch(SQLException e)
              e.printStackTrace();
              return null;
         finally
              UtilDB.closeResultSet(rs);
              UtilDB.closePreparedStatement(ps);
              pool.freeConnection(connection);
    public static ArrayList<Product> selectProducts()
         ConnectionPool pool = ConnectionPool.getInstance();
         Connection connection = pool.getConnection();
         PreparedStatement ps = null;
         ResultSet rs = null;
         String query = "SELECT A.PROD_SKU_ID, B.STYLE, B.DESCRIPTION, B.PRICE, A.COLOR, A.SIZE, C.THUMB_IMAGE, C.FULL_IMAGE "+
                        "FROM TB_PRODUCT_SKU A "+
                        "JOIN TB_PRODUCT B ON(A.PRODUCT_ID = B.PRODUCT_ID) "+
                        "JOIN TB_WEB_IMAGE C ON(C.WEB_IMAGE_ID = B.WEB_IMAGE_ID) "+
                        "WHERE A.QUANTITY > 0";
         try
              ps = connection.prepareStatement(query);
              rs = ps.executeQuery();
              ArrayList<Product> products = new ArrayList<Product>();
              while (rs.next())
                   Product p = new Product();
                   p.setCode(rs.getInt("PROD_SKU_ID"));
                   p.setStyle(rs.getString("STYLE"));
                   p.setDescription(rs.getString("DESCRIPTION"));
                   p.setPrice(rs.getDouble("PRICE"));
                   p.setColor(rs.getString("COLOR"));
                   p.setSize(rs.getString("SIZE"));
                   p.setThumb(rs.getString("THUMB_IMAGE"));
                   p.setFull(rs.getString("FULL_IMAGE"));
                   products.add(p);
              return products;
         catch(SQLException e)
              e.printStackTrace();
              return null;
         finally
              UtilDB.closeResultSet(rs);
              UtilDB.closePreparedStatement(ps);
              pool.freeConnection(connection);
}Display products.java
package category;
import java.io.IOException;
import java.sql.Connection;
import java.util.List;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import data.ConnectionPool;
import data.ProductDB;
import ecom.Product;
public class DisplayProducts extends HttpServlet{
     protected void doGet(HttpServletRequest request,
               HttpServletResponse response)
             throws ServletException, IOException
          List<Product> products = ProductDB.selectProducts();
          HttpSession session = request.getSession();
          session.setAttribute("products", products);
          String url = "/bracelets.jsp";
          RequestDispatcher dispatcher =
               getServletContext().getRequestDispatcher(url);
          dispatcher.forward(request, response);
}bracelets.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<table>
  <thead>
    <tr><th>ID</th><th>Product Name</th><th>Price<th></tr>
  </thead>
  <tbody>
    <c:forEach var="products" items="${products}">
      <!-- formatting probably required for price -->
      <tr>
      <td>${product.code}</td>
      <td>${product.style}</td>
      <td>${product.description}</td>
      <td>${product.price}</td>
      <td>${product.color}</td>
      <td>${product.size}</td>
      <td>${product.thumb}</td>
      <td>${product.full}</td>
      </tr>
    </c:forEach>
  </tbody>
</table>
</body>
</html>index.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<p><a href="product">Bracelets</a></p>
</body>
</html>Edited by: jonnyd9191 on Jul 14, 2008 1:49 PM