Java Servlets Sample

/*
 * @(#)Properties.java
 *
 * Copyright (c) 1998 Karl Moss. All Rights Reserved.
 *
 * You may study, use, modify, and distribute this software for any
 * purpose provided that this copyright notice appears in all copies.
 *
 * This software is provided WITHOUT WARRANTY either expressed or
 * implied.
 *
 * @author  Karl Moss
 * @version 1.0
 * @date    16Feb98
 *
 */

package javaservlets.samples;

import javax.servlet.*;
import javax.servlet.http.*;

/**
 * <p>This is a simple servlet that will echo information about
 * the client and also provide a listing of all of the
 * system properties on the server.
 */

public class Properties extends HttpServlet
{
  /**
    * <p>Performs the HTTP POST operation
    *
    * @param req The request from the client
    * @param resp The response from the servlet
    */

  public void doPost(HttpServletRequest req,
                     HttpServletResponse resp)
    throws ServletException, java.io.IOException
    {
      // Set the content type of the response
      resp.setContentType("text/html");

      // Create a PrintWriter to write the response
      java.io.PrintWriter out =
        new java.io.PrintWriter(resp.getOutputStream());

      // Print the HTML header
      out.println("<html>");
      out.println("<head>");
      out.println("<title>Java Servlets Sample - Properties</title>");
      out.println("</head>");
      out.println("<h2><center>");
      out.println("Information About You</center></h2>");
      out.println("<br>");

      // Create a table with information about the client
      out.println("<center><table border>");
      
      out.println("<tr>");
      out.println("<td>Method</td>");
      out.println("<td>" + req.getMethod() + "</td>");
      out.println("</tr>");

      out.println("<tr>");
      out.println("<td>User</td>");
      out.println("<td>" + req.getRemoteUser() + "</td>");
      out.println("</tr>");
      
      out.println("<tr>");
      out.println("<td>Client</td>");
      out.println("<td>" + req.getRemoteHost() + "</td>");
      out.println("</tr>");

      out.println("<tr>");
      out.println("<td>Protocol</td>");
      out.println("<td>" + req.getProtocol() + "</td>");
      out.println("</tr>");
      
      java.util.Enumeration enum = req.getParameterNames();
      while (enum.hasMoreElements()) {
        String name = (String) enum.nextElement();
        out.println("<tr>");
        out.println("<td>Parameter '" + name + "'</td>");
        out.println("<td>" + req.getParameter(name) + "</td>");
        out.println("</tr>");
      }
      
      out.println("</table></center><br><hr><br>");

      // Create a table with information about the server
      
      out.println("<h2><center>");
      out.println("Server Properties</center></h2>");
      out.println("<br>");

      out.println("<center><table border width=80%>");
      
      java.util.Properties props = System.getProperties();
      enum = props.propertyNames();
      
      while (enum.hasMoreElements()) {
        String name = (String) enum.nextElement();
        out.println("<tr>");
        out.println("<td>" + name + "</td>");
        out.println("<td>" + props.getProperty(name) + "</td>");
        out.println("</tr>");
      }
      out.println("</table></center>");
      
      // Wrap up
      out.println("</html>");
      out.flush();
    }

  /**
    * <p>Initialize the servlet. This is called once when the
    * servlet is loaded. It is guaranteed to complete before any
    * requests are made to the servlet
    *
    * @param cfg Servlet configuration information
    */

  public void init(ServletConfig cfg)
    throws ServletException
    {
      super.init(cfg);
    }

  /**
    * <p>Destroy the servlet. This is called once when the servlet
    * is unloaded.
    */

  public void destroy()
    {
      super.destroy();
    }
}
Method	" + req.getMethod() + "
User	" + req.getRemoteUser() + "
Client	" + req.getRemoteHost() + "
Protocol	" + req.getProtocol() + "
Parameter '" + name + "'	" + req.getParameter(name) + "