tomcat – Programmerbay

Create an application to add and multiply two numbers to the servlet to the user in apache tomcat server

Sandeep Verma — Sat, 07 Nov 2020 14:34:36 +0000

We are assuming that you have already downloaded and setup the Eclipse Environment and Tomcat server.

Here are the steps and the code to add and multiply two numbers to servlet in apache tomcat server

1) On Eclipse, create a new project and select Dynamic Web Project by ticking on producing deployment descriptor file.

2. Firstly hover on your newly created project, right-click on it and tab on new and select HTML file. ( or anything you want).

Index.html




Practical Work



First number   


Second number

3. Now, again hover on the project , right click on it and select new and tab on class that would create a java file.

Create a servlet class.

Add_Numbers.java

package com.programmerbay;
import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.http.*;
public class Add_Numbers extends HttpServlet{
public void service(HttpServletRequest request,HttpServletResponse response) throws IOException
{
int num1 = Integer.parseInt(request.getParameter("num1"));
int num2 = Integer.parseInt(request.getParameter("num2"));
int sum = num1 + num2;
int product = num1 * num2;
PrintWriter output = response.getWriter();
output.println("The Answer :"+sum +"\n The product :"+product);
}
}

4. Configure the Web.xml file which you find in Web Content folder.

web.xml





Add
com.programmerbay.Add_Numbers





Add
/add_me

5. Open the previously created index.html and run it by selecting the “restart server”.

Output:

Create an application to display addition and product of two numbers on the client side using JSP

Sandeep Verma — Sat, 07 Dec 2019 15:21:11 +0000

Simple code to display addition and product of two numbers using JSP.
1) Create a landing page in HTML.
Index.html





Practical Work



First number 
  


  Second number

2) Make a module in JSP that will print the sum and product of two numbers
add_multiply.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>




Insert title here


<%
int num1 = Integer.parseInt(request.getParameter("num1"));
int num2 = Integer.parseInt(request.getParameter("num2"));
int sum = num1 + num2;
int product = num1 * num2;
out.println("This is the sum = "+sum+"\n This is the product = "+product);
%>

Output:

Create an application to call a servlet from another servlet using RequestDispatcher in apache tomcat server

Sandeep Verma — Sat, 07 Dec 2019 15:10:49 +0000

Here’s the code to invoke a servlet from another servlet using RequestDispatcher interface.
1) Create index.html.

Index.html





Practical Work



WRITE

2) Now, create a basic servlet and pass the data of textbox field from index.html to First_Servlet.java. Use requestdispatcher to rely the data to other servlet.

First_Servlet.java

package com.programmerbay;

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 First_Servlet extends HttpServlet{
public void service(HttpServletRequest request,HttpServletResponse response) throws IOException, ServletException
{
String word = request.getParameter("word") ;
PrintWriter output = response.getWriter();

String word1 = word+".\n Now, It is calling second servlet";
// Dispatching it to second servlet
RequestDispatcher redirecting = request.getRequestDispatcher("second_servlet");
request.setAttribute("passingWord", word1);
redirecting.forward(request, response);
}

}

3) After that, write the code for second servlet that will handle the message or information from first servlet.

Second_Servlet.java

package com.programmerbay;

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

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

public class Second_Servlet extends HttpServlet{
public void service(HttpServletRequest request,HttpServletResponse response) throws IOException
{
String word = (String) request.getAttribute("passingWord");
PrintWriter output = response.getWriter();
output.println(word);

}
}

4) Edit the deployment descriptor.

Web.xml





Invoke_First
com.programmerbay.First_Servlet





Invoke_First
/first_servlet




Invoke_Second
com.programmerbay.Second_Servlet





Invoke_Second
/second_servlet

Output: