Store Content Of JTextField To Char

I was trying to store the content JTextField on char..... Here's the instruction of program--->>create a GUI program that convert letter into corresponding no. EXAMPLE:

if user enter "c" then it will output "3"......
like a=1,b=2,c=3,......

Here's my code

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class convert extends JFrame {
private static final int width = 400;
private static final int height = 300;
private JLabel EN,EQN;

[code]....