Java中setRolloverIcon()无法看出效果,求教，怎么改？

Question

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class Test extends JFrame implements ActionListener {
Test()
{
setSize(500,500);
setTitle("s");
setVisible(true);
setLayout(new GridLayout(2,1));
setDefaultCloseOperation(EXIT_ON_CLOSE);
ImageIcon icon1 = new ImageIcon("1.jpg");
ImageIcon icon2 = new ImageIcon("2.jpg");
JButton jb1 = new JButton(icon1);
JLabel jl = new JLabel();
jl.setText("标签");
jl.setToolTipText("头像"); //当光标停留在标签上的时候显示文本
jl.setIcon(icon2);
jl.setHorizontalTextPosition(SwingConstants.CENTER);
jb1.setRolloverIcon(icon1); //当光标停留在按钮上的时候显示图像
add(jb1);
jb1.addActionListener(this);
add(jl);
validate();
}
public void actionPerformed(ActionEvent e){
JInternalFrame in_window; //声明内部窗体
in_window = new JInternalFrame("内部窗体",true,true,true,true);
in_window.setSize(250,250);
in_window.setVisible(true);
add(in_window);
JTextArea text = new JTextArea(5,15); //创建文本区对象
in_window.add(text,BorderLayout.CENTER);
}
}
public class Demo1{
public static void main(String[] args){
new Test();
}
}

Answer 1

https://blog.csdn.net/u011393661/article/details/16330117