java left logo
java middle logo
java right logo
 

Home arrow Java EE Tips arrow Java Servlet arrow How to Redirect a Request using Servlet
 
 
Main Menu
Home
Java Tutorials
Book Reviews
Java SE Tips
Java ME Tips
Java EE Tips
Other API Tips
Java Applications
Java Libraries
Java Games
Java Network
Java Forums
Java Blog




Most Visited Tips
Java SE Tips
Java ME Tips
Java EE Tips
Other API Tips
Java Applications
Java Libraries
Java Games
Book Reviews
Top Rated Tips
Java SE Tips
Java ME Tips
Java EE Tips
Other API Tips
Java Applications
Java Libraries
Java Games
Book Reviews


Statistics
Registered Users: 4097
Java SE Tips: 614
Java ME Tips: 202
Java EE Tips: 183
Other API Tips: 779
Java Applications: 298
Java Libraries: 209
Java Games: 16
Book Reviews:
 
 
 
How to Redirect a Request using Servlet E-mail
User Rating: / 123
PoorBest 

One of the useful things a servlet can do using status codes and a header is redirecting a request. This is done by sending instructions for the client to use another URL in the responses. Redirection is generally used when a document moves (to send the client to new location), for load balancing, or for simple randomization.

This example shows a servlet that performs a random-redirect, sending a client to a random site selected from its site list.

import java.io.*;
import java.sql.Date;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class DemoSiteSelector extends HttpServlet{
    
    Vector sites = new Vector();
    Random random = new Random();
    
    public void init(ServletConfig config)throws ServletException{
        
        super.init(config);
        sites.addElement("http://www.google.com");
        sites.addElement("http://www.java-tips.org");
        sites.addElement("http://www.yahoo.com");
        sites.addElement("http://www.rediffmail.com");
        
    }
    public void doGet(HttpServletRequest req,HttpServletResponse res)
            throws ServletException,IOException{
        
        res.setContentType("text/plain");
        PrintWriter out= res.getWriter();
        int siteIndex = Math.abs(random.nextInt())%sites.size();
        String site = (Stringsites.elementAt(siteIndex);
        res.setStatus(res.SC_MOVED_TEMPORARILY);
        res.setHeader("Location", site);
        
    }
}

The actual redirection happened in two lines

  res.setStatus(res.SC_MOVED_TEMPORARILY);
  res.setHeader("Location", site);

These two lines can be simplified to one using the sendRedirect convenience method:

  res.sendRedirect(site);

  public void HttpServletRequest.sendRedirect(String locationthrows IOException

 Related Tips

 
< Prev   Next >

Page 1 of 0 ( 0 comments )

You can share your information about this topic using the form below!

Please do not post your questions with this form! Thanks.


Name (required)


E-Mail (required)

Your email will not be displayed on the site - only to our administrator
Homepage(optional)



Comment Enable HTML code : Yes No



 
       
         
     
 
 
 
   
 
 
java bottom left
java bottom middle
java bottom right
RSS 0.91 FeedRSS 1.0 FeedRSS 2.0 FeedATOM FeedOPML Feed

Home - About Us - Privacy Policy
Copyright 2005 - 2008 www.java-tips.org
Java is a trademark of Sun Microsystems, Inc.