Servlet Example

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class FirstCode extends HttpServlet {
public void init(ServletConfig config) throws ServletException {
super.init(config);
}

public void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
StringBuffer sb = new Stringbuffer();
String firstName = "";
String lastName = "";
int numPick = 0;
double amount = 0;
boolean inputCheck = true;
Vector varNames = new Vector();

if ((req.getParameter("firstName") != null) && (!req.getParameter("firstName").trim().equals(""))) {
firstName = req.getParameter("firstName").trim();
}
else {
inputCheck = false;
varNames.addElement("First Name");
}

if ((req.getParameter("lastName") != null) && (!req.getParameter("lastName").trim().equals(""))) {
lastName = req.getParameter("lastName").trim();
}
else {
inputCheck = false;
varNames.addElement("Last Name");
}

if ((req.getParameter("num") != null) && (!req.getParameter("num").trim().equals(""))) {
numPick = Integer.parseInt(req.getParameter("num").trim());
}
else {
inputCheck = false;
varNames.addElement("Pick Number");
}

if ((req.getParameter("amount") != null) && (!req.getParameter("amount").trim().equals(""))) {
amount = Double.parseDouble(req.getParameter("amount").trim());
}
else {
inputCheck = false;
varNames.addElement("Amount");
}

if (inputCheck) {
String remoteAddy = req.getRemoteAddr();
String remoteHost = req.getRemoteHost();
String scheme = req.getScheme();
String serverName = req.getServerName();
int serverPort = req.getServerPort();
double totalCost = numPick * amount;
NumberFormat nf = NumberFormat.getCurrencyInstance();
HtmlTop ht = new HtmlTop("Our First Servlet", null, "/styles/styles.css", null, null, null);
ht.doHtmlTop(sb);
HtmlBody hb = new HtmlBody();
sb = hd.doBodyTag(sb);
HtmlTable htb = new HtmlTable(null, null, null, "3", null, "2", "2", null, "100%");
sb = htb.doTableTag(sb);
HtmlTableTR htr = new HtmlTableTR();
sb = htr.doTableTR(sb);
HtmlTableTD htd = new HtmlTableTD(null, null, null, null, null, "2", "bodyBL", false, null, null, null);
sb = htd.doTableTD(sb);
sb.append(WELCOME);
sb = htd.endTD(sb);
sb = htr.endTR(sb);
sb = htr.doTableTR(sb);
HtmlTableTD htd2 = new HtmlTableTD(null, null, null, null, null, null, "bodyBL", false, null, null, "50%");
sb = htd2.doTableTD(sb);
sb.append("Your Name: ");
sb = htd.endTD(sb);
HtmlTableTD htd3 = new HtmlTableTD(null, null, null, null, null, null, "bodyBL", false, null, null, "100%");
sb = htd3.doTableTD(sb);
sb.append(firstName+" "+lastName);
sb = htd.endTD(sb);
sb = htr.endTR(sb);
sb = htr.doTableTR(sb);
sb = htd2.doTableTD(sb);
sb.append("The number you chose was: ");
sb = htd.endTD(sb);
sb = htd3.doTableTD(sb);
sb.append(numPick);
sb = htd.endTD(sb);
sb = htr.endTR(sb);
sb = htr.doTableTR(sb);
sb = htd2.doTableTD(sb);
sb.append("The Dollar amount you chose was: ");
sb = htd.endTD(sb);
sb = htd3.doTableTD(sb);
sb.append(nf.format(amount));
sb = htd.endTD(sb);
sb = htr.endTR(sb);
sb = htr.doTableTR(sb);
sb = htd2.doTableTD(sb);
sb.append("Your Total:");
sb = htd.endTD(sb);
sb = htd3.doTableTD(sb);
sb.append(nf.format(totalCost));
sb = htd.endTD(sb);
sb = htr.endTR(sb);
sb = htr.doTableTR(sb);
sb = htd2.doTableTD(sb);
sb.append("Your Remote Address: ");
sb = htd.endTD(sb);
sb = htd3.doTableTD(sb);
sb.append(remoteHost);
sb = htd.endTD(sb);
sb = htr.endTR(sb);
sb = htr.doTableTR(sb);
sb = htd2.doTableTD(sb);
sb.append("Server Protocol: ");
sb = htd.endTD(sb);
sb = htd3.doTableTD(sb);
sb.append(scheme);
sb = htd.endTD(sb);
sb = htr.endTR(sb);
sb = htb.endTableTag(sb);
sb = ht.endHtml(sb);
}
else {
FirstCodeError fce = new FirstCodeError();
fce.doErrorPage(varNames, out)
}
res.setContentType("text/html");
PrintWriter out = res.getWriter();
out.println(sb);
out.close();
}

public void doGet (HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
doPost(req, res);
}
};