Source Code for: "Migrating CGI Scripts," Vol. 3, Issue 1, p. 8

Listing 1.
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
public class TestWebServlet extends HttpServlet
{

    public void service(HttpServletRequest request,
HttpServletResponse response)
        throws ServletException, IOException
    {
// get input from the client using the HttpServletRequest parameter

// process the data

// return output to the client using the HttpServletResponse parameter
}

}

Listing 2.
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;

// File: TestWebServlet.java
// Listing 1
//
/**
*
* This servlet responds with a simple thank-you note displaying <p>
* the client's IP address.
*
* @author Chad (shod) Darby, darby@j-nine.com
* @version 1.369, 13 Nov 97
*
*/
public class TestWebServlet extends HttpServlet
{
    protected void service(HttpServletRequest request,
HttpServletResponse response)
        throws ServletException, IOException
    {
        String clientIPAddress = request.getRemoteAddr();
        String replyPage = null;

        // Build HTML page
        //
        replyPage = "<HTML><HEAD><TITLE>Test Web Servlet</TITLE></HEAD>";
        replyPage += "<BODY>";
        replyPage += "<P>Thanks for calling the servlet from " + clientIPAddress;
        replyPage += "</BODY></HTML>";

        // Set the content type of response
        //
        response.setContentType("text/html");

        // Get the output stream to the client response and send the page.
        // Note: The PrintWriter class is a new addition to Java 1.1
        //
        PrintWriter out = new
PrintWriter(response.getOutputStream());
        out.println(replyPage);
        out.flush();
        out.close();
    }
}

Listing 3.
import javax.servlet.*;
import javax.servlet.http.*;

import java.io.*;
import java.util.*;

// File: EchoEnvironmentServlet.java
// Listing 2
//
/**
* This servlet displays the CGI environment variables in a web page.
*
* @author Chad (shod) Darby, darby@j-nine.com
* @version 3.41, 2 Nov 1997
*
*/
public class EchoEnvironmentServlet extends HttpServlet
{

    public void service(HttpServletRequest request,
HttpServletResponse response)
     throws IOException
    {
        String replyPage = null;

        // Build the header for HTML page
        //
        replyPage = "<HTML><HEAD><TITLE>Echo Environment
Variables</TITLE></HEAD>";

replyPage += "<BODY>";

        // Echo the environment variables
        //
        replyPage += "<H2> Environment Variables </H2>";

        replyPage += "<p><b> Server Name: </b>" +
request.getServerName();
        replyPage += "<p><b> Server Port: </b>" +
request.getServerPort();
        replyPage += "<p><b> Server Protocol: </b>" +
request.getProtocol();
        replyPage += "<p><b> Servlet Name: </b>" +
request.getServletPath();

        replyPage += "<p><b> Method: </b>" + request.getMethod();
        replyPage += "<p><b> Path Info: </b>" +
request.getPathInfo();
        replyPage += "<p><b> Path Translated: </b>" +
request.getPathTranslated();
        replyPage += "<p><b> Query String: </b>" +
request.getQueryString();
        replyPage += "<p><b> Request URI: </b>" +
request.getRequestURI();

        replyPage += "<p><b> Remote Host: </b>" + request.getRemoteHost();
        replyPage += "<p><b> Remote Addr: </b>" + request.getRemoteAddr();
        replyPage += "<p><b> Remote User: </b>" +
request.getRemoteUser();
        replyPage += "<p><b> Authorization Type: </b>" + request.getAuthType();

replyPage += "<p><b> Content Type: </b>" +
request.getContentType();
replyPage += "<p><b> Content Length: </b>" +
request.getContentLength();

replyPage += "<hr>";

        // Just for kicks, let's loop thru and get the header info using an enumeration
        //
        replyPage += "<H2> Request Header Information </H2>";
        Enumeration e = request.getHeaderNames();
        String name;

        while (e.hasMoreElements())
        {
          name = (String) e.nextElement();
          replyPage += "<p><b>" + name + ": </b>" +
request.getHeader(name);
        }
        replyPage += "<hr>";

        // Build bottom of HTML page
        //
        replyPage += "</BODY> </HTML>";

        // Set the content-type for the response header
        // note: no need for extra carriage returns!
        //
        response.setContentType("text/html");

        // finally, send this formatted HTML page back to the client
        //
        PrintStream out = new PrintStream(response.getOutputStream());
        out.println(replyPage);
        out.close();
}

public String getServletInfo()
{
return "Echo Form Servlet, Chad (shod) Darby, 2 Nov 1997, www.j-nine.com";
}
}

Listing 4.



<HTML>
<HEAD>
<TITLE>Magazine Subscriptions</TITLE>
</HEAD>
<BODY>

<CENTER>
<H1>
Magazine Subscription Form</H1></CENTER>

<HR><FORM method="GET" action="http://127.0.0.1:8080/servlet/EchoMagazineForm">
<H3>
Name and Address</H3>

<TABLE>
<TR>
<TD>Name</TD>

<TD><INPUT type=text size=20 name="Name"></TD>
</TR>

<TR>
<TD>Address</TD>

<TD><INPUT type=text size=20 name="Address"></TD>
</TR>

<TR>
<TD>City</TD>

<TD><INPUT type=text size=20 name="City"></TD>
</TR>

<TR>
<TD>State</TD>

<TD><INPUT type=text size=20 name="State"></TD>
</TR>

<TR>
<TD>Zip Code</TD>

<TD><INPUT type=text size=20 name="Zip Code"></TD>
</TR>
</TABLE>

<H3>
Payment Method</H3>

<OL>
<LI>
Bill Me In Full <INPUT type="radio" name="Payment Method" value="Bill Me In Full"></LI>

<LI>
Bill Me In 3 Installments <INPUT type="radio" name="Payment Method" value="Bill Me In 3 Installments"></LI>

<LI>
Payment Enclosed <INPUT type="radio" name="Payment Method" checked value="Payment Enclosed"></LI>
</OL>

<TABLE>
<TR>
<TD></TD>

<TD><INPUT type=submit value="Subscribe"></TD>

<TD><INPUT type=reset value="Reset"></TD>
</TR>
</TABLE>
</FORM>
<HR>
</BODY>
</HTML>

Listing 5.
import javax.servlet.*;
import javax.servlet.http.*;

import java.io.*;
import java.util.*;

// File: EchoMagazineServlet.java
// Listing 4
//
/**
* This servlet displays the fields of a magazine subscription form in a web page.
*
*
*/
public class EchoMagazineServlet extends HttpServlet
{
private int counter;

public void init(ServletConfig config) throws ServletException
{
super.init(config);
counter = 0;
}

public void service(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException
{
String replyPage = null;

    // our servlet is being called, increment the counter
    //
    counter++;

    // Build HTML page�s header information
    //
    replyPage = "<HTML><HEAD><TITLE>Subscription Confirmation";
    replyPage += "</TITLE></HEAD>";

    replyPage += "<BODY>";
    replyPage += "<H1>Subscription Confirmation</H1>";
    replyPage += "<HR>";

    // Thank user for subscribing and show value of "counter"
    //
    replyPage += "Thank you for subscribing.";
    replyPage += "You are subscriber <b># " + counter + "</b>";
    replyPage += "<P>We will send the magazine to the mailing address below.";

    // Print out the values for form variables.
    // Notice we use HTML formatting to "spiff-up" the data
    //
    replyPage += "<UL>";
    replyPage += "<LI><B>Name:</B> " + request.getParameter("Name");
    replyPage += "<LI><B>Address:</B> " + request.getParameter("Address");
    replyPage += "<LI><B>City:</B> " + request.getParameter("City");
    replyPage += "<LI><B>State:</B> " + request.getParameter("State");
    replyPage += "<LI><B>Zip Code:</B> " + request.getParameter("Zip Code");
    replyPage += "<LI><B>Payment Method:</B> " +
request.getParameter("Payment Method");
    replyPage += "</UL>";

    replyPage += "<HR>";

    replyPage += "<P>" + this.getServletInfo();

    // Build bottom of HTML page
    //
    replyPage += "</BODY></HTML>";

    // Set the content-type for the response header
    //
    response.setContentType("text/html");

    // finally, send this formatted HTML page back to the client
    //
    PrintWriter out = new PrintWriter(response.getOutputStream());
    out.println(replyPage);
    out.close();
}

public String getServletInfo()
{
return "Echo Magazine Form Servlet v5.49, 2 Nov 1997";
}
}