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JAVA SERVLET

Applying Session into Basic Use

Here is an sample code using session tracking mechanism

import javax.servlet.*;
import javax.servlet.http.*;

/**
 * This is a simple servlet that uses session tracking and
 * to count the number of times a client session has
 * accessed this servlet.
 */

public class sesionprac extends HttpServlet
{
 //Define our counter key into the session
 static final String COUNTER_KEY = "Counter.count";

/**
  *Performs the HTTP GET operation
  *
  * @param req The request from the client
  * @param resp The response from the servlet
  */
 public void doGet(HttpServletRequest req,
                   HttpServletResponse resp)
  throws ServletException, java.io.IOException
  {
   //Get the session object for this client session.
   //The parameter indicates to create a session
   //object if one does not exist
   HttpSession session = req.getSession(true);

//Set the content type of the response
   resp.setContentType("text/html");
   
   //Get the PrintWriter to write the response
   java.io.PrintWriter out = resp.getWriter();

//Is there a count yet?
   int count = 1;
   Integer i = (Integer) session.getValue(COUNTER_KEY);

//If a previous count exists, set is
   if (i != null) {
   count = i.intValue() + 1;
  }

// Put the count back into the session
  session.putValue(COUNTER_KEY, new Integer (count));

// Print a standard header
  out.println("<html");
  out.println("<head>");
  out.println("<title>Session Counter</title>");
  out.println("</head>");
  out.println("<body>");
  out.println("Your session ID is <b>" +
                     count +
            "</b> times(s) during this browser session");

out.println("<form method=GET action=\"" +
  req.getRequestURI() + "\">");
  out.println("<input type=submit " +
  "value=\"Hit page agaon\">");
  out.println("</form>");

// Wrap up
  out.println("</body>");
  out.println("</html>");
  out.flush();
 }
}


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