Java game hit button only once

Question

Hi all I'm programming a 2D game (mario clone) and I have a little problem: is there a way to remove the fact that if I press the fire-button and i keep it pressed it start spawning milions of fireballs ?

Any help would be very appreciated, my thanks.

Edit: code

public void keyPressed(KeyEvent e){
    int key = e.getKeyCode();

    for (int i = 0; i < handler.object.size(); i++){
        GameObject tempObject = handler.object.get(i);

        if (tempObject.getId() == ObjectId.Player){
            if(key == KeyEvent.VK_D) tempObject.setVelX(5);
            if(key == KeyEvent.VK_A) tempObject.setVelX(-5);
            if(key == KeyEvent.VK_W && !tempObject.isJumping()) {
                tempObject.setJumping(true);
                tempObject.setVelY(-13);
            }
            if(key == KeyEvent.VK_SPACE){
                int velocity = tempObject.getLookingLR() * 5;
                float posX = tempObject.getX() + velocity;
                float posY =tempObject.getY()+32;
                handler.addObject(new Bullet(posX,posY, ObjectId.Bullet, velocity,handler));
                tempObject.setFiring(true);
            }
        }
    }

    if(key == KeyEvent.VK_ESCAPE){
        System.exit(1);
    }
}

Answer 1

You almost have it. You don't actually check your player's object to see if it's firing:

if(key == KeyEvent.VK_SPACE){
    int velocity = tempObject.getLookingLR() * 5;
    float posX = tempObject.getX() + velocity;
    float posY =tempObject.getY()+32;
    handler.addObject(new Bullet(posX,posY, ObjectId.Bullet, velocity,handler));
    tempObject.setFiring(true);
}

Should be:

if(key == KeyEvent.VK_SPACE && !tempObject.isFiring()){
    int velocity = tempObject.getLookingLR() * 5;
    float posX = tempObject.getX() + velocity;
    float posY =tempObject.getY()+32;
    handler.addObject(new Bullet(posX,posY, ObjectId.Bullet, velocity,handler));
    tempObject.setFiring(true);
}

You also need to add a keyReleased method that sets firing to false:

public void keyReleased(KeyEvent e) {
    //your code for getting key event and finding the player Object

    if(key == KeyEvent.VK_SPACE) {
        //Do any necessary cleanup of the firing here
        tempObject.setFiring(false);
    }
}