RequestDispatcher and sendRedirect not working.

package com.mindtree.travellingdiva.core.servlets;

import java.io.IOException;

import javax.servlet.RequestDispatcher;

import javax.servlet.Servlet;

import javax.servlet.ServletException;

import javax.servlet.http.HttpSession;

import org.apache.sling.api.SlingHttpServletRequest;

import org.apache.sling.api.SlingHttpServletResponse;

import org.apache.sling.api.servlets.HttpConstants;

import org.apache.sling.api.servlets.SlingAllMethodsServlet;

import org.osgi.framework.Constants;

import org.osgi.service.component.annotations.Component;

import org.osgi.service.component.annotations.Reference;

import com.mindtree.travellingdiva.core.dbservice.TDService;

@Component(service=Servlet.class,

property={

Constants.SERVICE_DESCRIPTION+"= Header Servlet",

"sling.servlet.methods=" + HttpConstants.METHOD_POST,

"sling.servlet.paths=/bin/LoginServlet",

"sling.servlet.resourceTypes="+"travellingdiva/components/structure/login",

"sling.servlet.extensions="+"txt"

})

public class LoginServlet extends SlingAllMethodsServlet{

/**

*

*/

private static final long serialVersionUID = 1L;

@Reference

TDService service;

@Override

protected void doPost(final SlingHttpServletRequest req, final SlingHttpServletResponse res) throws IOException

{

String username = req.getParameter("uname");

String password = req.getParameter("pass");

String st;

boolean result = service.verifyUser(username,password);

if(result==true)

{

HttpSession session = req.getSession();

st=""+session.getAttribute("username")+"  ";

st=st+"User Exist  ";

session.setAttribute("username", username);

session.setMaxInactiveInterval(1800);

st=st+session.getAttribute("username");

}

else

st="Invalid username/password";

//res.getWriter().write(st);

res.sendRedirect("/content/travellingdiva/project/home.html");

//RequestDispatcher rd = req.getRequestDispatcher("/content/travellingdiva/project/home.html");

/*try {

rd.include(req, res);

} catch (ServletException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}*/

}

}