JSP Program to convert Fahrenheit to Celsius

This post teaches you how to write a program to find Celsius from Fahrenheit using JSP web application. You already know JSP is a web application which is slightly different from the traditional Java programming.

In this program I have not used JSP and Servlet but only JSP code embedded in the HTML page, basically Single page web application.

Let’s write JSP code to convert Fahrenheit to Celsius:

<%
    //check if post request
    if("POST".equalsIgnoreCase(request.getMethod()))
    {
        //define variables
        float fahrenheit, celsius;
        //get the value from text box and convert into float
        fahrenheit = Float.parseFloat(request.getParameter("name"));
        //apply the formula
        celsius = (fahrenheit - 32) * 5/9;
        //print the value
        out.print("<h3>Celsius: "+celsius+"</h3>");
    }
%>

The above JSP script gets the value from Text box named as “fahrenheit” and then converts into Celsius by using the below formula:

celsius = (fahrenheit – 32) * 5/9;

Here is the entire JSP code embedded with HTML:

<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>Convert Fahrenheit to Celsius JSP Program - Tutorialsmade.com</title>
    </head>
    <body>
        <h2>Convert Fahrenheit to Celsius in JSP - Tutorialsmade.com!</h2>
        <form action="" method="post">            
            <label>Enter Fahrenheit: </label><input type="text" name="fahrenheit" />
        </form>
    </body>
</html>

<%
    //check if post request
    if("POST".equalsIgnoreCase(request.getMethod()))
    {
        //define variables
        float fahrenheit, celsius;
        //get the value from text box and convert into float
        fahrenheit = Float.parseFloat(request.getParameter("fahrenheit"));
        //apply the formula
        celsius = (fahrenheit - 32) * 5/9;
        //print the value
        out.print("<h3>Celsius: "+celsius+"</h3>");
    }
%>