FlavorListServlet.java Source code

Introduction

Here is the source code for FlavorListServlet.java

Source

/**
*  Copyright (c) 2002 by Phil Hanna
*  All rights reserved.
*  
*  You may study, use, modify, and distribute this
*  software for any purpose provided that this
*  copyright notice appears in all copies.
*  
*  This software is provided without warranty
*  either expressed or implied.
*/
import java.io.*;
import java.net.*;
import java.sql.*;
import java.util.*;

import javax.servlet.*;
import javax.servlet.http.*;

/**
* Returns the list of the most popular flavors
*/
public class FlavorListServlet extends HttpServlet {
    public static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";

    public static final String URL = "jdbc:mysql://localhost/IceCream";

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        PrintWriter out = response.getWriter();
        response.setContentType("text/html");

        // Get the bounds of the ranks to be listed
        // or use defaults

        int lowLimit = getLimit(request.getParameter("lowLimit"), 0);
        int highLimit = getLimit(request.getParameter("highLimit"), 100);

        Connection con = null;
        try {

            // Connect to the ice cream database

            Class.forName(JDBC_DRIVER);
            con = DriverManager.getConnection(URL);

            // Run a query to get the top flavors

            String sql = "SELECT  RANK, NAME" + "   FROM flavors" + "   WHERE RANK BETWEEN ? AND ?"
                    + "   ORDER BY RANK";
            PreparedStatement pstmt = con.prepareStatement(sql);
            pstmt.setInt(1, lowLimit);
            pstmt.setInt(2, highLimit);
            ResultSet rs = pstmt.executeQuery();

            // Print as an ordered list

            out.println("<ol>");
            while (rs.next()) {
                int rank = rs.getInt(1);
                String name = rs.getString(2);
                out.println("   <li>" + name + "</li>");
            }
            out.println("</ol>");
        } catch (SQLException e) {
            throw new ServletException(e.getMessage());
        } catch (ClassNotFoundException e) {
            throw new ServletException(e.getMessage());
        }

        // Close the database

        finally {
            if (con != null) {
                try {
                    con.close();
                } catch (SQLException ignore) {
                }
            }
        }
    }

    /**
    * Subroutine to get the integer value of one of
    * the limit parameters.
    * @param parm the parameter value, which may be null
    * @param defaultValue the default value
    */
    private static int getLimit(String parm, int defaultValue) {
        int limit = defaultValue;
        if (parm != null) {
            try {
                limit = Integer.parseInt(parm);
            } catch (NumberFormatException ignore) {
            }
        }
        return limit;
    }
}