Prentice Hall and Sun Microsystems. Personal use only; do not redistribute.
6.3 A Front End to Various Search Engines
135
501 (Not Implemented)
The 501 (
SC_NOT_IMPLEMENTED
) status notifies the client that the 
server doesn't support the functionality to fulfill the request. It is used, 
for example, when the client issues a command like 
PUT
 that the server 
doesn't support. 
502 (Bad Gateway)
A value of 502 (
SC_BAD_GATEWAY
) is used by servers that act as proxies 
or gateways; it indicates that the initial server got a bad response from 
the remote server. 
503 (Service Unavailable)
A status code of 503 (
SC_SERVICE_UNAVAILABLE
) signifies that the 
server cannot respond because of maintenance or overloading. For 
example, a servlet might return this header if some thread or database 
connection pool is currently full. The server can supply a 
Retry After
header to tell the client when to try again. 
504 (Gateway Timeout)
A value of 504 (
SC_GATEWAY_TIMEOUT
) is used by servers that act as 
proxies or gateways; it indicates that the initial server didn't get a timely 
response from the remote server. This status code is new in HTTP 1.1. 
505 (HTTP Version Not Supported)
The 505 (
SC_HTTP_VERSION_NOT_SUPPORTED
) code means that the 
server doesn't support the version of HTTP named in the request line. 
This status code is new in HTTP 1.1.
6.3 A Front End to Various Search 
Engines
Listing 6.1 presents an example that makes use of the two most common sta 
tus codes other than 200 (OK): 302 (Found) and 404 (Not Found). The 302
code is set by the shorthand 
sendRedirect
 method of 
HttpServletRe 
sponse
, and 404 is specified by 
sendError
. 
In this application, an HTML form (see Figure 6 1 and the source code in
Listing 6.3) first displays a page that lets the user choose a search string, the
number of results to show per page, and the search engine to use. When the
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