Servlet: Session tracking using URLReWriting

URL rewriting.

Ø  In this URL Rewriting session tracking, the data of every individual client is given back to the client browser in the form anchoring message (hyper link) along with some parameters and values. So that the client browser will display the anchoring message by hiding the parameters and values.

Ø  When the same client click the anchoring message then the browser will automatically send those parameters and values to the application.

Ø  It will always work whether cookie is disabled or not (browser independent).

Ø  Extra form submission is not required on each pages.

Ø  It will work only with links.

Ø  It can send Only textual information.

The following example demonstrate how to use the URL Rewriting session tracking in servlet application.

In this example, we are maintaining the state of the user using link. For this purpose, we are appending the name of the user in the query string and getting the value from the query string in another page.

index.html

=======

<form action="servlet1"> 

Name:<input type="text" name="sname"/><br/> 

<input type="submit" value="submit"/> 

</form>

web.xml

======

<?xml version="1.0" encoding="UTF-8"?>

<web-app version="3.1" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd">

<servlet> 

<servlet-name>s1</servlet-name> 

<servlet-class>FirstServlet</servlet-class> 

</servlet> 

 

<servlet-mapping> 

<servlet-name>s1</servlet-name> 

<url-pattern>/servlet1</url-pattern> 

</servlet-mapping> 

 

<servlet> 

<servlet-name>s2</servlet-name> 

<servlet-class>SecondServlet</servlet-class> 

</servlet> 

 

<servlet-mapping> 

<servlet-name>s2</servlet-name> 

<url-pattern>/servlet2</url-pattern> 

</servlet-mapping> 

</web-app>

The URL pattern of this class must be /s1, this will receive the request with one parameter "sname" and Submit as get Request.

FirstServlet.java

===========

import java.io.*; 

import javax.servlet.ServletException;

import javax.servlet.http.*; 

public class FirstServlet extends HttpServlet { 

 

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

        response.setContentType("text/html"); 

        PrintWriter out = response.getWriter();          

        String n=request.getParameter("sname"); 

        out.print("Welcome "+n);   

        out.println("<br /><br />");

        out.print("<a href='servlet2?uname="+n+"'>Please click here for your details</a>");                   

        out.close();          

    }  

} 

The URL pttern of this class must be /s2, this will receive the request with one parameter "uname" when we click on anchoring message

SecondServlet.java

=============

import java.io.*; 

import javax.servlet.ServletException;

import javax.servlet.http.*; 

 

public class SecondServlet extends HttpServlet {   

@Override

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

        response.setContentType("text/html"); 

        PrintWriter out = response.getWriter();          

        //getting value from the query string 

        String name=request.getParameter("uname"); 

        out.print("Hello "+name);  

        out.close();     

    }

}