使用JPanel需要main函数吗

[nonesite]

源程序如下：
import java.awt.*;
import javax.swing.*;
class MyDrawPanel extends JPanel{
public void paintComponent(Graphics g){
g.setColor(Color.orange);
g.fillRect(20,50,100,100);
}
}运行时错误：java.lang.NoSuchMethodError: main
Exception in thread "main"
添加main（）函数后：
import java.awt.*;
import javax.swing.*;
class MyDrawPanel extends JPanel{
public static void main(String[] args){
MyDrawPanel abc = new MyDrawPanel();
}
public void paintComponent(Graphics g){
g.setColor(Color.orange);
g.fillRect(20,50,100,100);
}
}
可以运行，但是没有结果，谁来抱我解决下，不胜感激

[dr_lou]

需要JFrame容器吧。

[学习Java中]

		JFrame jf = new JFrame();
		jf.add(abc);
		jf.setSize(100, 200);
		jf.setVisible(true);

[dr_lou]

package com.xuz.csdn.oct09;

import java.awt.*;
import javax.swing.*;

class MyDrawPanel extends JPanel {
	public static void main(String[] args) {
		MyDrawPanel abc = new MyDrawPanel();
		JFrame jf = new JFrame();
		jf.setContentPane(abc);
		jf.setBounds(20,50,400,200);
		jf.setVisible(true);
	}

	public void paintComponent(Graphics g) {
		g.setColor(Color.orange);
		g.fillRect(20, 50, 100, 100);
	}
}

[kala197]

import java.awt.*;

public class TestPanel extends Frame {

    public TestPanel(String str) {
        super(str);
    }
    
    public static void main(String []args){
        TestPanel frm=new TestPanel("Frame with Panel");
        Panel pnl=new Panel();
        frm.setSize(250,150);
        frm.setBackground(Color.blue);
        frm.setLayout(null);
        pnl.setSize(150,100);
        pnl.setBackground(Color.RED);
        frm.add(pnl);
        frm.setVisible(true);
    }
}

[nonesite]

多谢大家，解决问题了