swing中JPanel如何实现分组框的效果以及设置边框颜色

代码如下：

import java.awt.FlowLayout;
import java.awt.Frame;
import java.awt.GridLayout;

import javax.swing.BorderFactory;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class JFrameBackground extends JFrame {
 public JFrameBackground(){
  this.setTitle("我的swing界面"); 
  this.setLayout(new FlowLayout());
  JPanel buttonPanel = new JPanel();
  buttonPanel.setBorder(BorderFactory.createTitledBorder("分组框")); //设置面板边框，实现分组框的效果，此句代码为关键代码

  buttonPanel.setBorder(BorderFactory.createLineBorder(Color.red));//设置面板边框颜色
  JButton button = new JButton("我的按钮");
  buttonPanel.add(button);
  this.setSize(300, 300);
  this.getContentPane().add(buttonPanel);
  this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  this.setVisible(true);
 }
 
 public static void main(String[] args) {
  new JFrameBackground();
 }

}