Prentice Hall and Sun Microsystems. Personal use only; do not redistribute.
4.4 Sending Compressed Web Pages
105
DILBERT reprinted by permission of United Syndicate, Inc.
Explorer on non Windows platforms generally do not support content encod 
ing. Fortunately, browsers that support this feature indicate that they do so
by setting the 
Accept Encoding
 request header. Listing 4.2 shows a servlet
that checks this header, sending a compressed Web page to clients that sup 
port gzip encoding and sending a regular Web page to those that don't. The
result showed a tenfold speedup for the compressed page when a dialup con 
nection was used. In repeated tests with Netscape 4.7 and Internet Explorer
5.0 on a 28.8K modem connection, the compressed page averaged less than 5
seconds to completely download, whereas the uncompressed page consis 
tently took more than 50 seconds.
Core Tip
Gzip compression can dramatically reduce the download time of long text 
pages.
Implementing compression is straightforward since gzip format is built in
to the Java programming languages via classes in 
java.util.zip
. The serv 
let first checks the 
Accept Encoding
 header to see if it contains an entry for
gzip. If so, it uses a 
GZIPOutputStream
 to generate the page, specifying
gzip
 as the value of the 
Content Encoding
 header. You must explicitly call
close
 when using a 
GZIPOutputStream
. If gzip is not supported, the servlet
uses the normal 
PrintWriter
 to send the page. To make it easy to create
benchmarks with a single browser, I also added a feature whereby compres 
sion could be suppressed by including 
?encoding=none
 at the end of the
URL. 
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