Java Tutorial/Servlet/Redirect

Redirect Servlet Based on Path Info And Query String

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
public class MyServlet extends HttpServlet {
  public void doGet(HttpServletRequest req, HttpServletResponse res)
                               throws ServletException, IOException {
    // Determine the site where they want to go
    String site = req.getPathInfo();
    String query = req.getQueryString();
    // Handle a bad request
    if (site == null) {
      res.sendError(res.SC_BAD_REQUEST, "Extra path info required");
    }
    // Cut off the leading "/" and append the query string
    // We"re assuming the path info URL is always absolute
    String url = site.substring(1) + (query == null ? "" : "?" + query);
    // Log the requested URL and redirect
    log(url);  // or write to a special file
    res.sendRedirect(url);
  }
}

Redirect Servlet by Setting Response Location

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
public class MyServlet extends HttpServlet {
  Vector sites = new Vector();
  Random random = new Random();
  public void init() throws ServletException {
    sites.addElement("http://www.jexp.ru/Code/Java/CatalogJava.htm");
    sites.addElement("http://www.jexp.ru/Tutorial/Java/CatalogJava.htm");
    sites.addElement("http://www.jexp.ru/Article/Java/CatalogJava.htm");
    sites.addElement("http://www.jexp.ru/Product/Java/CatalogJava.htm");
  }
  public void doGet(HttpServletRequest req, HttpServletResponse res)
                               throws ServletException, IOException {
    res.setContentType("text/html");
    PrintWriter out = res.getWriter();
    int siteIndex = Math.abs(random.nextInt()) % sites.size();
    String site = (String)sites.elementAt(siteIndex);
    res.setStatus(res.SC_MOVED_TEMPORARILY);
    res.setHeader("Location", site);
  }
}