CurrencyConverter.java

package com.exchange;

import java.io.*;

import java.net.*;

import java.util.*;

import javax.servlet.*;

import javax.servlet.http.*;

import java.io.InputStream;

import java.net.*;

import com.google.gson.*;


classRecv

{

private String lhs;

private String rhs;

private String error;

private String icc;

public Recv(

{

}

public String getLhs()

{

return lhs;

}

public String getRhs()

{

return rhs;

}

}

public classConvertextendsHttpServlet {

/**

* Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.

* @param request servlet request

* @param response servlet response

* @throws ServletException if a servlet-specific error occurs

* @throws IOException if an I/O error occurs

*/

protected void processRequest(HttpServletRequest req, HttpServletResponse resp)

throws ServletException, IOException {

String query = "";

String amount = "";

String curTo = "";

String curFrom = "";

String submit = "";

String res = "";

HttpSession session;

resp.setContentType("text/html;charset=UTF-8");

PrintWriter out = resp.getWriter();

/*Read request parameters*/

amount = req.getParameter("amount");

curTo = req.getParameter("to");

curFrom = req.getParameter("from");

/*Open a connection to google and read the result*/

try {

query = "http://www.google.com/ig/calculator?hl=en&q=" + amount + curFrom + "=?" + curTo;

URL url = new URL(query);

InputStreamReader stream = new InputStreamReader(url.openStream());

BufferedReader in = new BufferedReader(stream);

String str = "";

String temp = "";

while ((temp = in.readLine()) != null) {

str = str + temp;

}

/*Parse the result which is in json format*/

Gson gson = new Gson();

Recv st = gson.fromJson(str, Recv.class);

String rhs = st.getRhs();

rhs = rhs.replaceAll("�", "");

/*we do the check in order to print the additional word(millions,billions etc)*/

StringTokenizer strto = new StringTokenizer(rhs);

String nextToken;

out.write(strto.nextToken());

nextToken = strto.nextToken();

if( nextToken.equals("million") || nextToken.equals("billion") || nextToken.equals("trillion"))

{

out.println(" "+nextToken);

}

} catch (NumberFormatException e) {

out.println("The given amount is not a valid number");

}

}

// <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">

/**

* Handles the HTTP <code>GET</code> method.

* @param request servlet request

* @param response servlet response

* @throws ServletException if a servlet-specific error occurs

* @throws IOException if an I/O error occurs

*/

@Override

protected void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

processRequest(request, response);

}

/**

* Handles the HTTP <code>POST</code> method.

* @param request servlet request

* @param response servlet response

* @throws ServletException if a servlet-specific error occurs

* @throws IOException if an I/O error occurs

*/

@Override

protected void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

processRequest(request, response);

}

/**

* Returns a short description of the servlet.

* @return a String containing servlet description

*/

@Override

public String getServletInfo() {

return "Short description";

}

}