Example: SessionSample.java

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

public class SessionSample extends HttpServlet {

  public void doGet (HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {

    // Step 1: Get the Session object
    boolean create = true;
    HttpSession session = request.getSession(create);

    // Step 2: Get the session data value
    Integer ival = (Integer) session.getValue ("sessiontest.counter");
    if (ival == null) {
      ival = new Integer (1);
    }
    else {
      ival = new Integer(ival.intValue () + 1);
    }
    session.putValue ("sessiontest.counter", ival);

    // Step 3: Output the page
    response.setContentType("text/html");
    PrintWriter out = response.getWriter();
    out.println("<html>");
    out.println("<head><title>Session Tracking Test</title></head>");
    out.println("<body>");
    out.println("<h1>Session Tracking Test</h1>");
    out.println("You have hit this page " + ival + " times" + "<br>");
    out.println("Your " + request.getHeader("Cookie"));
    out.println("</body></html>");
  }
}