Request dispatcher forwarding request

For login example we are using user mail id and password. if both are correct then we are forwaring to home.jsp page if any on of mail id or password is in correct then it will forwarded back to index.jsp page with appropriate error message.

index.jsp

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>Login Page</title>
    </head>
    <body>
        <h1>Login Page</h1>
        <div style="color:  red">
            <%
              String message = (String) request.getAttribute("error");
                if(message!=null){
              out.println(message);
                }
            %>
        </div>
        <form action="login" method="post">
            Mail Id        : <input type="text" name="mailId" placeholder="Enter your mail id"/><br><br>
            Password : <input type="password" name="password" placeholder="Enter your password"/><br><br>
            <input type="submit" value="Login"/>
        </form>
    </body>
</html>

<%@page contentType="text/html" pageEncoding="UTF-8"%>

<!DOCTYPE html>

<html>

<head>

<title>Login Page</title>

</head>

<body>

<h1>Login Page</h1>

String message = (String) request.getAttribute("error");

if(message!=null){

out.println(message);

}

</div>

Mail Id : <input type="text" name="mailId" placeholder="Enter your mail id"/><br><br>

Password : <input type="password" name="password" placeholder="Enter your password"/><br><br>

</form>

</body>

</html>

Login.java

package ebhor.servlet;

import java.io.IOException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet(name = "Login", urlPatterns = {"/login"})
public class Login extends HttpServlet {

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        String mailId = request.getParameter("mailId");
        String password = request.getParameter("password");
        System.out.println("Mail id "+mailId+"  password "+password);
        if (mailId.equals("adminuser@gmail.com") && password.equals("123456")) {
            System.out.println("Successfully Login");
            RequestDispatcher dispatcher = getServletContext().getRequestDispatcher("/home.jsp");
            dispatcher.forward(request, response);
        } else {
            System.out.println("Mail id or password is incorrect");
            request.setAttribute("error", "Please enter correct username and/or password");
            RequestDispatcher dispatcher = getServletContext().getRequestDispatcher("/index.jsp");
            dispatcher.forward(request, response);
        }
    }
}

package ebhor.servlet;

import java.io.IOException;

import javax.servlet.RequestDispatcher;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

@WebServlet(name = "Login", urlPatterns = {"/login"})

public class Login extends HttpServlet {

@Override

protected void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

response.setContentType("text/html;charset=UTF-8");

String mailId = request.getParameter("mailId");

String password = request.getParameter("password");

System.out.println("Mail id "+mailId+" password "+password);

if (mailId.equals("[email protected]") && password.equals("123456")) {

System.out.println("Successfully Login");

RequestDispatcher dispatcher = getServletContext().getRequestDispatcher("/home.jsp");

dispatcher.forward(request, response);

} else {

System.out.println("Mail id or password is incorrect");

request.setAttribute("error", "Please enter correct username and/or password");

RequestDispatcher dispatcher = getServletContext().getRequestDispatcher("/index.jsp");

dispatcher.forward(request, response);

}

home.jsp

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>Home Page</title>
    </head>
    <body>
        <h1>Welcome  User</h1>
        <h3>Your mail id  is <%=request.getParameter("mailId")%></h3>
        <h3>Your password is  <%=request.getParameter("password")%></h3>

    </body>
</html>

<%@page contentType="text/html" pageEncoding="UTF-8"%>

<!DOCTYPE html>

<html>

<head>

</head>

<body>

<h1>Welcome User</h1>

<h3>Your password is <%=request.getParameter("password")%></h3>

</body>

</html>

Result

1258_first

If user id and/or password is incorrect then it will be redirected to index.jsp page with appropriate error message.

1258_second

Using correct mailid and password [email protected] and 123456

1258_third