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My Small Web Project - but has some problems - please help ...

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posted 19 years ago

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Hi ,
Can you please deploy this small project . This project has 1 jsp , 2 servlet & 3 java class .

functionality needed :
--------------------

It should display 3 combo for continent , country & city . when user select any continent & the second combo ( country )should automatically get update based on the value of first combo , after then user will select country in second combo so third combo ( city ) should autmatically get update based on the value of second combo .

please deploy it , It is not proper as per the need . And please suggest me how can I acheive this functionality ...

Thank you very much ...

home.jsp
--------
<HTML>
<HEAD><TITLE>
Home
</TITLE></HEAD>
<BODY>
<%@ page import = "java.util.*" %>
<%@ page import ="com.my.*" %>
<FORM name = "continentForm" action = "./ContinentProcessor" method = "get">
<SELECT name = "continent" onchange="continentSubmit()">
<OPTION>[Select]</OPTION>
<OPTION>Asia</OPTION>
<OPTION>Europe</OPTION>
<OPTION>North America</OPTION>
</SELECT>
</FORM>
<SCRIPT>
 
function continentSubmit() {
document.continentForm.submit();
}
</SCRIPT>
<FORM name = "countryForm" action = "./CountryProcessor" method = "get">
 
<% 
List countryList = (List) request.getAttribute("countryList");
if(countryList !=null) {
String countryName = null;
%><SELECT name = "country" onchange="countrySubmit()">
<OPTION>[Select]</OPTION>
<%
for(Iterator i = countryList.iterator(); i.hasNext() :wink:  {
countryName = ((Country)i.next()).getCountryName();
out.println(countryName);
%>
<OPTION><%= countryName%></OPTION>
<%
}
%></SELECT><%
}
%>
</FORM>
<SCRIPT>
 
function countrySubmit() {
document.countryForm.submit();
}
</SCRIPT>
 
<% 
List cityList = (List) request.getAttribute("cityList");
if(cityList !=null) {
String cityName = null;
%><SELECT>
<OPTION>[Select]</OPTION>
<%
for(Iterator i = cityList.iterator(); i.hasNext() :wink:  {
cityName = (String)i.next();
out.println(cityName);
%>
<OPTION><%= cityName%></OPTION>
<%
}
%></SELECT><%
}
%>
 
</BODY>
</HTML>

ContinentProcessor.java
-----------------------
 
package com.my;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Iterator;
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;
 
public class ContinentProcessor extends HttpServlet {
 
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {

String continentFromUser = req.getParameter("continent");
System.out.println(continentFromUser);
Loader loader = new Loader();
List continentList = loader.load(); 
String continentFromList = null;
List countryList = null;
for(Iterator i = continentList.iterator(); i.hasNext() :wink:  {
Continent continentObject = (Continent) i.next();
continentFromList = continentObject.getContinentName();
if(continentFromUser.equals(continentFromList)) {
countryList = continentObject.getCountryList();
break;
}
}

req.setAttribute("countryList",countryList);

RequestDispatcher dispatcher = req.getRequestDispatcher("./home.jsp");
dispatcher.forward(req, resp);

}
}

CountryProcessor.java
---------------------
 
package com.my;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
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;

public class CountryProcessor extends HttpServlet {
 
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {

String countryFromUser = req.getParameter("country");
System.out.println(countryFromUser);
Loader loader = new Loader();
List continentList = loader.load(); 
List countryList = null;
List cityList = null;
String countryFromList = null;

for(Iterator i = continentList.iterator(); i.hasNext() :wink:  {
countryList = ((Continent)i.next()).getCountryList();

for(Iterator j = countryList.iterator(); j.hasNext() :wink:  {
Country countryObject = (Country)j.next();
countryFromList = countryObject.getCountryName();
if(countryFromUser.equals(countryFromList)) {
cityList = countryObject.getCityList();
break;
}

}
}
 
req.setAttribute("cityList",cityList);
 
RequestDispatcher dispatcher = req.getRequestDispatcher("./home.jsp");
dispatcher.forward(req, resp); 
 
}
 
}

Loader.java
-----------
 
/* Right now I am hardcoding the list but later I will make it from 
the XML file */
 
package com.my;
import java.util.ArrayList;
import java.util.List;
 
public class Loader {

private List continentList = null;

public List load() {
continentList = loadContinentList();
return continentList;
}

private List loadContinentList() {
List continentList = new ArrayList();
continentList.add(loadContinentObject("Asia"));
continentList.add(loadContinentObject("Europe"));
continentList.add(loadContinentObject("North America"));
return continentList;
}

private Continent loadContinentObject(String continentName) {
Continent continentObject = null;
if(continentName == "Asia") {
continentObject = new Continent(continentName,loadCountryList(continentName));
}
if(continentName == "Europe") {
continentObject = new Continent(continentName,loadCountryList(continentName));
}
if(continentName == "North America") {
continentObject = new Continent(continentName,loadCountryList(continentName));
}
return continentObject;
}

private List loadCountryList(String continentName) {
List countryList = new ArrayList();
if(continentName == "Asia") {
countryList.add(loadCountryObject("India"));
countryList.add(loadCountryObject("China"));
countryList.add(loadCountryObject("Japan"));
}
if(continentName == "Europe") {
countryList.add(loadCountryObject("United Kingdom"));
countryList.add(loadCountryObject("France"));
countryList.add(loadCountryObject("Russia"));
countryList.add(loadCountryObject("Italy"));
}
if(continentName == "North America") {
countryList.add(loadCountryObject("United States"));
countryList.add(loadCountryObject("Canada"));
}
return countryList;
}

private Country loadCountryObject(String countryName) {
Country countryObject = null;
if(countryName == "India") {
countryObject = new Country(countryName,loadCityList(countryName));
}
if(countryName == "China") {
countryObject = new Country(countryName,loadCityList(countryName));
}
if(countryName == "Japan") {
countryObject = new Country(countryName,loadCityList(countryName));
}
if(countryName == "Russia") {
countryObject = new Country(countryName,loadCityList(countryName));
}
if(countryName == "United Kingdom") {
countryObject = new Country(countryName,loadCityList(countryName));
}
if(countryName == "France") {
countryObject = new Country(countryName,loadCityList(countryName));
}
if(countryName == "Italy") {
countryObject = new Country(countryName,loadCityList(countryName));
}
if(countryName == "United States") {
countryObject = new Country(countryName,loadCityList(countryName));
}
if(countryName == "Canada") {
countryObject = new Country(countryName,loadCityList(countryName));
}
return countryObject;
}
 
private List loadCityList(String countryName) {
List cityList = new ArrayList();
if(countryName == "India") {
cityList.add("Mumbai");
cityList.add("Pune");
cityList.add("Indore");
cityList.add("Chennai");
cityList.add("Ratlam");
cityList.add("Banglore");
}
if(countryName == "China") {
cityList.add("Beijing ");
}
if(countryName == "Japan") {
cityList.add("Tokyo");
}
if(countryName == "Russia") {
cityList.add("Moscow");
}
if(countryName == "United Kingdom") {
cityList.add("London");
cityList.add("Sheffield");
}
if(countryName == "France") {
cityList.add("Paris");
}
if(countryName == "Italy") {
cityList.add("Rome");
}
if(countryName == "United States") {
cityList.add("New York");
cityList.add("Texas");
cityList.add("New Jersey");
cityList.add("California");
cityList.add("Florida");
cityList.add("Washington");
}
if(countryName == "Canada") {
cityList.add("Alberta");
cityList.add("British Columbia");
cityList.add("Nova Scotia");
}
return cityList;
}
}

Shailesh Chandra

Ranch Hand

Posts: 1087

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posted 19 years ago

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rathi ,

I haven't read your complete code.

you need to modify your JSp code as below
I am doing it for country

also you need to add request attribute in your servlet, and forward them across all servlet.

in code below I assume that there is an attribte holding the value of country that is selected by user.

thanks

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