Having problems with my random number guess game

I need help with my java code, I can't find how to get back to guessing a number again. What I mean is that if you type in the wrong number it won't use the random thingy so you can guess again. But it will ask you to put in a new number. So I need your help with this random guessing program.

import javax.swing.*;
import java.util.Random;

public class Projekt_1 {

public static void main(String[] args) {
String number;
JOptionPane.showMessageDialog(null, "Welcome to the guessing game!" + "\nYou     gonna guess a number between 1 and 20." + "\nHOPE YOU LIKE IT!:)");

Random amount = new Random();
int guessnumber = anount.nextInt(20);
int random;

number = JOptionPane.showInputDialog("Guess a number between 1 and 20");
random = Integer.parseInt(number);
while (random == guessnumber){

JOptionPane.showMessageDialog(null, "You won!" + "\nYour number was" + "" + guessnumber);      
}
if (random < guessnumber){
  number = JOptionPane.showInputDialog("Your number is to high :(" + "\nType in a new lower number!"); 
  random = Integer.parseInt(number);
}
else if (random > guessnumber){
  number = JOptionPane.showInputDialog("Your number is to low :(" + "\nType in a higher number!"); 
  random = Integer.parseInt(number);
}
}
}