2c. Session Creation and Destruction


index.html

<html>
<head>
<title>Session Demo</title>
</head>
<form action="Page1" method="get" >
Enter User ID <input type="text" name="txtName">
<br> <input type="reset" ><input type="submit" > </form>
</html>



Page1.java

package mypack;


import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class Page1 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException { response.setContentType("text/html;charset=UTF-8"); PrintWriter out = response.getWriter();
out.println("<html><head><title>Servlet Page1</title></head>");
HttpSession hs = request.getSession(true);
if(hs.isNew()){

out.println("<body bgcolor=yellow>");

String name = request.getParameter("txtName");
hs.setAttribute("uname", name);
hs.setAttribute("visit", "1");
out.println("<h1>Welcome First Time</h1>");
}
else{
out.println("<h1>Welcome Again</h1>");
int visit = Integer.parseInt((String)hs.getAttribute("visit"))+1; out.println("<h1>You Visited "+visit+"Times</h1>"); hs.setAttribute("visit", ""+visit); }
out.println("<h1>Your Session ID "+hs.getId()+"</h1>");
out.println("<h1>You Logged in at "+new java.util.Date(hs.getCreationTime())+"</h1>"); out.println("<h1><a href=Page2>Click for Page 2 </a></h1>"); out.println("<h1><a href=Page3>Click for Page 3 </a></h1>");
out.println("<h1><a href=Page4>Click for Page 4 </a></h1>");
out.println("<h1><a href=LogoutServlet>Click to Terminate Session </a></h1>");
out.println("</body>");
out.println("</html>");
}

}



Page2.java


package mypack;


import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class Page2 extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { response.setContentType("text/html;charset=UTF-8"); PrintWriter out = response.getWriter();
out.println("<html><head><title>Servlet Page2</title></head>");
HttpSession hs = request.getSession(false);
out.println("<h1>Welcome Again on Page No. 2</h1>");
int visit = Integer.parseInt((String)hs.getAttribute("visit"))+1;
out.println("<h1>You Visited "+visit+"Times</h1>");
hs.setAttribute("visit", ""+visit);
out.println("<h1>Your Session ID "+hs.getId()+"</h1>");
out.println("<h1>You Logged in at "+new java.util.Date(hs.getCreationTime())+"</h1>"); out.println("<h1><a href=Page1>Click for Page 1 </a></h1>");
out.println("<h1><a href=Page3>Click for Page 3 </a></h1>");
out.println("<h1><a href=Page4>Click for Page 4 </a></h1>");
out.println("<h1><a href=LogoutServlet>Click for Terminate Session </a></h1>");
out.println("</body>");
out.println("</html>");
}
}





Repeat the code from Page2.java in Page3.java and Page4.java with relevant changes.

LogoutServlet.java

package mypack;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class LogoutServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException { response.setContentType("text/html;charset=UTF-8"); PrintWriter out = response.getWriter();
out.println("<html><head><title>Servlet LogoutServlet</title></head>");
out.println("<body>");
javax.servlet.http.HttpSession hs = request.getSession();
if(hs != null) hs.invalidate();
out.println("<h1>You are Logged out now........</h1>");
out.println("</body>");
out.println("</html>");
}
}





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