Forum:

Servlets

Why isn't my servlet not sending response when I press the submit button?

Greenhorn

Posts: 25

posted 11 months ago

Number of slices to send:

Optional 'thank-you' note:

Send

I am creating a simple project that has a form that accepts a username and password and using servlets and request dispatcher.

If the username and password are correct then the response goes to another servlet or else it stays on index page.

However, when I click on submit button nothing happens?

How do I resolve this error?

Here is my code, Servlet1

Servlet1

package com.servlets;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class Servlet1 extends HttpServlet{
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // TODO Auto-generated method stub
        RequestDispatcher rd;
        PrintWriter out=resp.getWriter();
        String name=req.getParameter("user_name");
        String password=req.getParameter("password");
        
        if("Sourabh".equals(name) && "Chamya@123".equals(password)) {
            rd=req.getRequestDispatcher("/next");
            rd.forward(req, resp);
        }
        else {
            out.print("invalid name and password");
            rd=req.getRequestDispatcher("/index.html");
            rd.include(req, resp);
        }
        
    }
}

Servlet 2

index.html

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" id="WebApp_ID" version="4.0">
  <display-name>RequestDispatcher</display-name>
  
  <servlet>
    <servlet-name>
        servlet1
    </servlet-name>
    <servlet-class>
        com.servlets.Servlet1
    </servlet-class>
  </servlet>
  
  <servlet-mapping>
    <servlet-name>
        servlet1
    </servlet-name>
    <url-pattern>
        /login
    </url-pattern>
  </servlet-mapping>
  
  <servlet>
    <servlet-name>
        servlet2
    </servlet-name>
    <servlet-class>
        com.servlets.Servlet2
    </servlet-class>
  </servlet>
  
  <servlet-mapping>
    <servlet-name>
        servlet2
    </servlet-name>
    <url-pattern>
        /next
    </url-pattern>
  </servlet-mapping>
  
  
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.jsp</welcome-file>
    <welcome-file>default.htm</welcome-file>
  </welcome-file-list>
</web-app>

Bear Bibeault

Sheriff

Posts: 67748

173

I like...

posted 11 months ago

Number of slices to send:

Optional 'thank-you' note:

Send

1) Check your spelling (hint: <from action="login" method="post">)

2) The action of "login" should start with the context path to ensure that the servlet will be addressed correctly.

[Asking smart questions] [About Bear] [Books by Bear]

Sourabh Chavan

Greenhorn

Posts: 25

posted 11 months ago

Number of slices to send:

Optional 'thank-you' note:

Send

Bear Bibeault wrote:1) Check your spelling (hint: <from action="login" method="post">)

2) The action of "login" should start with the context path to ensure that the servlet will be addressed correctly.

I did it but now the form cannot be seen but just the raw html code when In include the incorrect username and password.

Bear Bibeault

Sheriff

Posts: 67748

173

I like...

posted 11 months ago

Number of slices to send:

Optional 'thank-you' note:

Send

rd.include(req, resp);

Is that really what you want to be doing?

[Asking smart questions] [About Bear] [Books by Bear]

Ron McLeod

Marshal

Posts: 4533

572

I like...

posted 11 months ago

Number of slices to send:

Optional 'thank-you' note:

Send

Post the contents of the updated index.html file.

Sourabh Chavan

Greenhorn

Posts: 25

posted 11 months ago

Number of slices to send:

Optional 'thank-you' note:

Send

Ron McLeod wrote:Post the contents of the updated index.html file.

Sourabh Chavan

Greenhorn

Posts: 25

posted 11 months ago

Number of slices to send:

Optional 'thank-you' note:

Send

Bear Bibeault wrote:rd.include(req, resp);

Is that really what you want to be doing?

Yes

Bear Bibeault

Sheriff

Posts: 67748

173

I like...

posted 11 months ago

Number of slices to send:

Optional 'thank-you' note:

Send

Yes

Really?

[Asking smart questions] [About Bear] [Books by Bear]

Sourabh Chavan

Greenhorn

Posts: 25

posted 11 months ago

Number of slices to send:

Optional 'thank-you' note:

Send

Bear Bibeault wrote:

Yes

Really?

I am watching a tutorial and this is what the person has done.

Sourabh Chavan

Greenhorn

Posts: 25

posted 11 months ago

Number of slices to send:

Optional 'thank-you' note:

Send

Sourabh Chavan wrote:

Bear Bibeault wrote:

Yes

Really?

I am watching a tutorial and this is what the person has done.

Bear Bibeault

Sheriff

Posts: 67748

173

I like...

posted 11 months ago

Number of slices to send:

Optional 'thank-you' note:

Send

You can believe the tutorial (in the face of it clearly not doing what you want), or you can question its assumptions.

Can you explain why you feel include is the correct approach (other than "it's in the tutorial")?

[Asking smart questions] [About Bear] [Books by Bear]

Sourabh Chavan

Greenhorn

Posts: 25

posted 11 months ago

Number of slices to send:

Optional 'thank-you' note:

Send

Bear Bibeault wrote:You can believe the tutorial (in the face of it clearly not doing what you want), or you can question its assumptions.

Can you explain why you feel include is the correct approach (other than "it's in the tutorial")?

What include does it basically incudes a html file in the response.
We want to respond with the same html file
We do not want to forward the response to another servlet which is done by forward().

Bear Bibeault

Sheriff

Posts: 67748

173

I like...

posted 11 months ago

Number of slices to send:

Optional 'thank-you' note:

Send

You shouldn't be quoting your own reply. It makes it really confusing to see what's the quoter, and your new info.

What include does it basically incudes a html file in the response.
We want to respond with the same html file
We do not want to forward the response to another servlet which is done by forward().

Not quite. By doing an include, you're including the html file into the POST. You never want a POST sitting in the browser.

A new request is created when the form is submitted, so it has nothing to do with the original html file, so "We want to respond with the same html file" doesn't make sense in this context.

What you want, is a redirect, to create a new GET for the html file.

You might want to read this article when you get a chance, regarding how to properly deal with requests in a Java web app.

[Asking smart questions] [About Bear] [Books by Bear]