JAVA 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();
}

}