Question

I am new here and have been working on this all evening. I know this should be simple and I am just missing something silly. I have a jsp page and a servlet (code below). I am trying to search out a customer from my database, which works. However, if the customer is not found I want to post an error message on the same jsp page so that the user can possibly re-enter the phone number in case they made a mistake. I am unsure how to do this. I can forward to the new “customer” page just fine and I have tried successfully to redirect back to the same page, but I don’t know how to put the message there. Help please!

jsp page:

    <%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1" isELIgnored="false" %>
    <%@ page import="java.util.*" %>  
    <%@ include file="staticpages/pageHeader.html" %>
        <br />      
            <hr />
            <br />
            <form name="custform" method="POST" action="ChooseCustomer.do" >
            <span class="sectionheader">Look Up Customer by Phone Number:</span>

            <input type="text" name="phone1" size="3" maxlength="3" onKeyUp="checklen(this)" />             
            <input type="text" name="phone2" size="3" maxlength="3" onKeyUp="checklen(this)" />
            <input type="text" name="phone3" size="4" maxlength="4" onKeyUp="checklen(this)" />
            <input type="submit" name="formaction" value="Search" />
            <input type="submit" name="formaction" value="Enter New Customer" />
            </form> 
    <%@ include file="staticpages/pageFooter.html" %>

servlet code:

package pizzapkg;

import java.io.IOException;
import java.sql.ResultSet;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class ChooseCustomer
 */
@WebServlet("/ChooseCustomer")
public class ChooseCustomer extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /** @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)  */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        Customer c = null;
        if (request.getParameter("formaction").equals("Search")) {

                Database db = (Database) getServletContext().getAttribute("db");
            /* Search Database for existing customer */
            String searchPhone = request.getParameter("phone1") 
                    + request.getParameter("phone2") 
                    + request.getParameter("phone3");
            String sql = "SELECT * FROM customers WHERE cust_phone=\"" + searchPhone + "\";";
            ResultSet rs;
            try {
                rs = db.runSqlQuery(sql);
                rs.next();
                c = new Customer(rs.getString("cust_id"), rs.getString("cust_fname"), 
                        rs.getString("cust_lname"), rs.getString("cust_address"), 
                        rs.getString("cust_city"), rs.getString("cust_state"), 
                        rs.getString("cust_zip"), rs.getString("cust_phone"),
                        rs.getString("cust_notes"));
            } catch (Exception e) { e.printStackTrace(); }
            request.setAttribute("customer", c);        
        }
        RequestDispatcher rd = request.getRequestDispatcher("/customer.jsp");
        rd.forward(request, response);
    }
}

PS This the the first time I have built a servlet so this is all new to me. I love examples so any help you can give will be greatly appreciated.

Answer 1

You may set a flag in request object inside your servlet, if the customer is not found e.g.

          request.setAttribute("customerFound", "No");

In your JSP, put a JSP scriptlet to check the request attribute and print the message wherever you want e.g. if you want the message after your <HR/> then:

        <hr />
        <% if("No".equals(request.getAttribute("customerFound")) { %>
            <div style="color: red">No customer found</div>
        <% } %>
        <br />

I am sharing the very basic way of achieving your desired result.