Tutorials : Server-Side Web Applications Using Servlets and JSP :
: Setting HTTP Status Codes

Contents
Setting HTTP Status Codes
Specifying Status Codes
HTTP 1.1 Status Codes and Their Meaning
Example: Search Engine Front End

Setting HTTP Status Codes

1. Overview

When a Web server responds to a request from a browser or other Web client, the response typically consists of a status line, some response headers, a blank line, and the document. Here is a minimal example: 
HTTP/1.1 200 OK
Content-Type: text/plain

Hello World
The status line consists of the HTTP version, an integer that is interpreted as a status code, and a very short message corresponding to the status code. In most cases, all of the headers are optional except for Content-Type, which specifies the MIME type of the document that follows. Although most responses contain a document, some don't. For example, responses to HEAD requests should never include a document, and there are a variety of status codes that essentially indicate failure, and either don't include a document or only include a short "error message document".

Servlets can perform a variety of tasks by manipulating the status line and the response headers. For example, they can forward the user to other sites; indicate that the attached document is an image, Adobe Acrobat file, or (most commonly) HTML file; tell the user that a password is required to access the document; and so forth. This section will discuss the various different status codes and what can be accomplished with them, while the following section will discuss the response headers.

NEXT

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

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.

Elsewhere on internet.com:

WebDeveloper Java
Lots of Java information on webdeveloper.com

WDVL Java
Thorough Java resource at the Web Developer's Virtual Library.

ScriptSearch Java
Hundreds of free Java code files to download.

jGuru: Your View of the Java Universe
Customizable portal with online training, FAQs, regular news updates, and tutorials.