Lets try to create one html page and retrieve data to a servlet and add those data and send this data to another servlet to print.
Let’s create a sequence of steps to achieve this:
- Create an HTML form to collect two numbers from the user.
- Create a servlet to retrieve the numbers from the form, add them, and then forward the result to another servlet.
- The second servlet will display the result.
Step 1: Create the HTML Form
Create an HTML file named input.html.
<!DOCTYPE html>
<html>
<head>
<title>Number Addition</title>
</head>
<body>
<h2>Add Two Numbers</h2>
<form action="add" method="post">
<label for="number1">Number 1:</label>
<input type="text" id="number1" name="number1"><br><br>
<label for="number2">Number 2:</label>
<input type="text" id="number2" name="number2"><br><br>
<input type="submit" value="Submit">
</form>
</body>
</html>
Step 2: Create the First Servlet (AddServlet)
Create a new Java class named AddServlet.java. This servlet will retrieve the numbers from the form, add them, and forward the result to the second servlet.
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.RequestDispatcher;
@WebServlet("/add")
public class AddServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// Retrieve data from the form
int number1 = Integer.parseInt(request.getParameter("number1"));
int number2 = Integer.parseInt(request.getParameter("number2"));
// Calculate the sum
int sum = number1 + number2;
// Set the sum as a request attribute
request.setAttribute("sum", sum);
// Forward the request to the ResultServlet
RequestDispatcher dispatcher = request.getRequestDispatcher("result");
dispatcher.forward(request, response);
}
}
Step 3: Create the Second Servlet (ResultServlet)
Create a new Java class named ResultServlet.java. This servlet will display the result sent from the AddServlet.
import java.io.IOException;
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("/result")
public class ResultServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// Retrieve the sum from the request attribute
int sum = (int) request.getAttribute("sum");
// Display the result
response.setContentType("text/html");
response.getWriter().println("<h1>Result</h1>");
response.getWriter().println("<p>The sum is: " + sum + "</p>");
}
}
Explanation
- HTML Form (
input.html):- Collects two numbers from the user and submits the form data to the
/addURL using a POST request.
- Collects two numbers from the user and submits the form data to the
- AddServlet (
AddServlet.java):- Mapped to
/add. - Retrieves the two numbers from the form, calculates their sum, and sets the result as a request attribute.
- Forwards the request to
ResultServletusingRequestDispatcher.
- Mapped to
- ResultServlet (
ResultServlet.java):- Mapped to
/result. - Retrieves the sum from the request attribute and displays it.
- Mapped to
Step 4: Deploy Your Application
- Place
input.htmlin the web directory (e.g.,webapps/your_project_nameif using Tomcat). - Compile and deploy
AddServlet.javaandResultServlet.javaas part of your web application. - Start your server (Tomcat) and navigate to
http://localhost:8080/your_project_name/input.htmlin your web browser.
When you fill out the form and click “Submit,” the AddServlet will handle the request, add the numbers, and forward the result to the ResultServlet, which will then display the sum.