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/**
* 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;
}
}
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