4.2 Create a web form which processes servlet and demonstrates use of cookies and sessions.

login.html

<html>
    <head>
        <title> Login Page </title>
    </head>

    <body>
        <form action="loginservlet" method="post">
            <table>
                <tr>
                    <td>User Name: </td>
                    <td> <input type="text" name="name"> </td>
                </tr>
                <tr>
                    <td>Password: </td>
                    <td> <input type="password" name="pass"> </td>
                </tr>
                <tr>
                    <td> </td>
                    <td> <input type="submit" name="submit" value="SUBMIT"> </td>
                </tr>
        </form>
    </body>
</html>

loginservlet.java
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 loginservlet extends HttpServlet  
{ 
    protected void doPost (HttpServletRequest req, HttpServletResponse   res) throws ServletException, IOException {
    res.setContentType("text/html"); 
    PrintWriter out=res.getWriter(); 
    String name=req.getParameter("name"); 
    String password=req.getParameter("pass"); 
  
    if(name.equals("Mayur") && password.equals("Thakkar"))  { 
        HttpSession session=req.getSession(); 
        session.setAttribute("Name", name); 
        out.println("<br/><h1>Welcome :"+ name + "</h1> "); out.println("<br/> <a href=profile> Click here </a>");   
    } 
    else{ 
        out.println("<h1>You Have entered Wrong Password </h1>"); out.println("<br/> <a href=login.html> Click here </a> to Login");  } 
    } 
  
}

Profile.java 
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 profile extends HttpServlet  
{ 
    protected void doGet (HttpServletRequest req, HttpServletResponse   res) throws ServletException, IOException  { 
  
    res.setContentType("text/html"); 
    PrintWriter out=res.getWriter(); 
  
    HttpSession session=req.getSession(false); 
    if(session!=null) { 
        String name=(String) session.getAttribute("Name");  out.println("Welcome," + name); 
        out.println("<h1>This is Session Program. </h1> ");
        out.println("<a href=logoutservlet> Click here to Logout </a>");  
    } 
    else {  
        out.println("<br> <h1> Plz Login First</h1>"); 
        out.println("<br/> <a href=login.html> Click here </a> to Login");  
    } 
 }  
}

Logoutservlet.java
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 logoutServlet extends HttpServlet  
{ 
    public void doGet (HttpServletRequest req,HttpServletResponse res)   throws IOException, ServletException  { 
    res.setContentType("text/html"); 
    PrintWriter out=res.getWriter(); 
    
    HttpSession session=req.getSession(); 
    session.invalidate(); 
    
    out.println("<br> <h1>You have successfully Logout </h1>");  out.println("<br/> <a href=login.html> Click here </a> to Login");  } 
    
}

Web.xml
<servlet> 
    <servlet-name>loginservlet</servlet-name>  <servlet-class>loginservlet</servlet-class>  
</servlet>  

<servlet> 
    <servlet-name>logoutservlet</servlet-name>  <servlet-class>logoutServlet</servlet-class>  
</servlet> 

<servlet> 
    <servlet-name>profile</servlet-name>  <servlet-class>profile</servlet-class>  
</servlet>  

<servlet-mapping> 
    <servlet-name>profile</servlet-name>  <url-pattern>/profile</url-pattern>
</servlet-mapping> 

<servlet-mapping> 
    <servlet-name>logoutservlet</servlet-name>  <url-pattern>/logoutservlet</url-pattern>  
</servlet-mapping> 

<servlet-mapping> 
    <servlet-name>loginservlet</servlet-name>  <url-pattern>/loginservlet</url-pattern>  
</servlet-mapping>

Happy Coding :)