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Aim: A web application for implementation: The user is first served a login page which takes user's name and password. After Submitting the details the server checks these values against the data from a database and takes the following decisions.

  • If name and password matches, serves a welcome page with user’s full
  • If name matches and password doesn’t match, then serves “password mismatch” page
  • If name is not found in the database, serves a registration page, where user’s full name is asked and on submitting the full name, it stores, the login name, password and full name in the database (hint: use session for storing the submitted login name and password)
File: login7.html

<form name="login" method="post" action="sls">
    <table width="370" border="1" align="center" style="background: silver;">
        <tr height="25">
            <th colspan="4" align="center">User Login</th>
        </tr>
        <tr>
            <td>User Name</td>
            <td><input type="text" name="uname" required></td>
        </tr>
        <tr>
            <td>Password</td>
            <td><input type="password" name="pwd" required></td>
        </tr>
        <tr align="center">
            <td colspan="2">
                <input type="submit" name="ok" value="Submit">
            </td>
        </tr>
    </table>
</form>
File: StudentLoginServlet.java

package pres;
import java.io.IOException; 
import java.io.PrintWriter; 
import java.sql.Connection; 
import java.sql.DriverManager; 
import java.sql.ResultSet; 
import java.sql.SQLException; 
import java.sql.Statement; 
import javax.servlet.*;
import javax.servlet.http.*;

public class StudentLoginServlet extends HttpServlet { 
    private Connection con = null;

    public void init() throws ServletException { 
        try {
            DriverManager.registerDriver(new com.mysql.jdbc.Driver());
            con = DriverManager.getConnection("jdbc:mysql://localhost:3306/mrecw","root","naresh");
        } catch (Exception e) { 
            e.printStackTrace();
        }
    }

    public void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html"); 
        Statement statement = null;
        ResultSet rs = null; 
        HttpSession session = req.getSession();
        String uname = req.getParameter("uname"); 
        String pwd = req.getParameter("pwd");

        try {
            PrintWriter out = resp.getWriter(); 
            statement = con.createStatement();
            rs = statement.executeQuery("select uname, pwd, fullname from login where uname='" + uname + "' ");

            if (rs.next()) {
                if (pwd.equals(rs.getString("pwd"))) { 
                    session.setAttribute("fullname", rs.getString("fullname"));
                    RequestDispatcher rd = req.getRequestDispatcher("home8.jsp");
                    rd.forward(req, resp);
                } else {
                    out.println("<h3 align='center' style='color:red;'>Password Mismatch</h3>");
                    RequestDispatcher rd = req.getRequestDispatcher("login7.html"); 
                    rd.include(req, resp);
                }
            } else {
                out.println("<h3 align='center' style='color:red;'>Please register your details</h3>");
                RequestDispatcher rd = req.getRequestDispatcher("registration.jsp"); 
                rd.include(req, resp);
            }
        } catch (SQLException e) { 
            e.printStackTrace();
        }
    }
}
File: home8.jsp

<h2>Hi <%=(String)session.getAttribute("fullname") %>!</h2><br/>
<h2>Welcome to the home page - You are successfully logged in</h2><br/>
<a href="login7.html">Back</a>
File: web.xml

<web-app>
    <servlet>
        <servlet-name>sls</servlet-name>
        <servlet-class>pres.StudentLoginServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>sls</servlet-name>
        <url-pattern>/sls</url-pattern>
    </servlet-mapping>
</web-app>
Output:

user.htmlpassword.htmlregister.htmllogin.html (2)success.html

;