Practical 1A: Create a simple calculator application using servlet.


Step 1: Create a new project 

Step 2: Select java web → web Application 

--> index.html


<html>
<head>
<title>Calculator App</title>
</head>
<body> 
<form action="CalculatorServlet" method="post" >


Enter First Number <input type="text" name="txtN1" ><br> Enter Second Number <input type="text" name="txtN2" ><br> Select an Operation


<input type="radio" name="opr" value="+">ADDTION 
<input type="radio" name="opr" value="*">MULTIPLY <input type="radio" name="opr" value="/">DIVIDE
<input type="radio" name="opr" value="-"> Substraction
 <br> <input type="reset">


<input type="submit" value="Calculate" >


</form>
</body>
</html>



Step 3:  Add a new Servlet to source package

-Name the servlet and package

-Check “Add information to deployment descriptor” to add servlet into web.xml But preferably use annotation.


CalculatorServlet.java



package mypack;


import java.io.IOException;


import java.io.PrintWriter;


import javax.servlet.ServletException;


import javax.servlet.http.HttpServlet;


import javax.servlet.http.HttpServletRequest;


import javax.servlet.http.HttpServletResponse;


public class CalculatorServlet extends HttpServlet {


public void doGet(HttpServletRequest request, HttpServletResponse response)


throws ServletException, IOException { response.setContentType("text/html;charset=UTF-8);
PrintWriter out = response.getWriter();


out.println("<html><head><title>Servlet CalculatorServlet</title></head><body>");               double n1 = Double.parseDouble(request.getParameter("txtN1"));


double n2 = Double.parseDouble(request.getParameter("txtN2"));
double result =0;
String opr=request.getParameter("opr");
if(opr.equals("+")) result=n1+n2;
if(opr.equals("-")) result=n1-n2; 
if(opr.equals("*")) result=n1*n2; 
if(opr.equals("/")) result=n1/n2; 

out.println("<h1> Result = "+result); 
 out.println("</body></html>");
}    



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