Prentice Hall and Sun Microsystems. Personal use only; do not redistribute.
152
Chapter 7 Generating the Server Response: HTTP Response Headers
Refresh
This header indicates how soon (in seconds) the browser should ask for 
an updated page. For example, to tell the browser to ask for a new copy 
in 30 seconds, you would specify a value of 30 with 
response.setIntHeader("Refresh", 30)
Note that 
Refresh
 does not stipulate continual updates; it just speci 
fies when the next update should be. So, you have to continue to sup 
ply 
Refresh
 in all subsequent responses, and sending a 204 (
No 
Content
) status code stops the browser from reloading further. For an 
example, see Section 7.3 (Persistent Servlet State and Auto Reloading 
Pages).
Instead of having the browser just reload the current page, you can 
specify the page to load. You do this by supplying a semicolon and a 
URL after the refresh time. For example, to tell the browser to go to 
http://host/path
 after 5 seconds, you would do the following.
response.setHeader("Refresh", "5; URL=http://host/path")
This setting is useful for  splash screens,  where an introductory image 
or message is displayed briefly before the real page is loaded.
Note that this header is commonly set by 
CONTENT="5; URL=http://host/path">
in the 
HEAD
 section of the HTML page, rather than as an explicit header 
from the server. That usage came about because automatic reloading or 
forwarding is something often desired by authors of static HTML pages. 
For servlets, however, setting the header directly is easier and clearer. 
This header is not officially part of HTTP 1.1 but is an extension sup 
ported by both Netscape and Internet Explorer. 
Retry After
This header can be used in conjunction with a 503 (
Service Unavail 
able
) response to tell the client how soon it can repeat its request.
Server
This header identifies the Web server. Servlets don't usually set this; the 
Web server itself does. 
Second edition of this book: www.coreservlets.com; Sequel: www.moreservlets.com.
Servlet and JSP training courses by book's author: courses.coreservlets.com.






footer




 

 

 

 

 Home | About Us | Network | Services | Support | FAQ | Control Panel | Order Online | Sitemap | Contact

jsp web hosting

 

Our partners: PHP: Hypertext Preprocessor Best Web Hosting Java Web Hosting Jsp Web Hosting Cheapest Web Hosting

Visionwebhosting.net Business web hosting division of Web Design Plus. All rights reserved