The Java Boutique: Server-Side Web Applications using Java Servlets versions 2.1/2.2 and JavaServer Pages (JSP) version 1.0: A Tutorial First Servlets

Articles : Tutorials : Server-Side Web Applications Using Servlets and JSP :

Part 3: First Servlets

Contents

Basic Servlet Structure

A Simple Servlet Generating Plain Text

A Servlet that Generates HTML

Simple HTML-Building Utilities

3. A Servlet that Generates HTML

Most servlets generate HTML, not plain text as in the previous example. To do that, you need two additional steps:

tell the browser that you're sending back HTML

and modify the println statements to build a legal Web page.
The first step is done by setting the Content-Type response header. In general, headers can be set via the setHeader method of HttpServletResponse, but this is such a common task that there is also a special setContentType method just for this purpose. Note that you need to set response headers before actually returning any of the content via the PrintWriter. Here's an example:

3.1 HelloWWW.java

You can also download the source or try it on-line.

package hall;

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

public class HelloWWW extends HttpServlet {
  public void doGet(HttpServletRequest request,
                    HttpServletResponse response)
      throws ServletException, IOException {
    response.setContentType("text/html");
    PrintWriter out = response.getWriter();
    out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0 " +
                                        "Transitional//EN\">\n" +
                "<HTML>\n" +
                "<HEAD><TITLE>Hello WWW</TITLE></HEAD>\n" +
                "<BODY>\n" +
                "<H1>Hello WWW</H1>\n" +
                "</BODY></HTML>");
  }
}

3.2 HelloWWW Result

HelloWWW Servlet Output

This tutorial is now available as a book: Core Servlets and JavaServer Pages by Marty Hall, published by Sun Microsystems Press. Read all about it at CoreServlets.com

Server-Side Web Applications using Java Servlets versions 2.1/2.2 and JavaServer Pages (JSP) version 1.0: A Tutorial
© 1999-2000 Marty Hall.
All source code freely available for unrestricted use.
Created for work in the Research and Technology Development Center of the Johns Hopkins University Applied Physics Lab, for courses in the Johns Hopkins Part-Time MS Program in Computer Science, and for various industry seminars and on-site Java short courses.
Please note that this is a first draft of the tutorial, so please send corrections, comments, and suggestions to me at hall@apl.jhu.edu.
Reprinted with permission from the author. Click here to visit the original version

Applet Index
(sorted alphabetically)
A B C D E F G H I J K
L M N O P Q R S T U
V W X Y Z #s

The Java Source
(applets w/source code)
A B C D E F G H I J K
L M N O P Q R S T U
V W X Y Z

How to Add Java Applets to Your Site

New on the Java Boutique:

New Review:

Time Management Made Easy with the Quartz Enterprise Job Scheduler
Why not just use the Java timer API? This open source scheduling API boasts simplicity, ease-of-integration, a well-rounded feature set, and it's free!

New Applet:

Reverse Complement
Reverse Complement is a simple applet that converts DNA or RNA sequences into three useful formats.