图片按钮ImageButton

//按钮上放图片，图片按钮
            JButton enterButton = new JButton("");
            //由.png图片获得URL对象
            URL url = getClass().getResource("enter.png");
            //由URL获得ImageIcon对象
            ImageIcon imageIcon = new ImageIcon(url);   
            enterButton.setBounds(0, 40,imageIcon.getIconWidth(), imageIcon.getIconHeight());
            //设置ImageIcon 
            enterButton.setIcon(imageIcon);
            enterButton.setContentAreaFilled(false);    // 取消填充区域
            enterButton.setBorder(null);                // 取消边框