方式一：

package com.swing.test;

import javax.swing.ImageIcon;

import javax.swing.JFrame;

public class aa extends JFrame{

    String image = new String("aaa.gif"); //建立一个字符串保存要用的图标的路径，关于java的路径请参考其它文档

    ImageIcon test = new ImageIcon(image); //建立一个ImageIcon类，产生setIconImage()方法需要的Image数据

    public aa() {

        super("演示自定义标题栏的图标的方法");

        this.setIconImage(test.getImage()); //设置标题栏的图标为face.gif

        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        this.show();

        //this.setTitle("sdfsdf");

        this.setSize(400,200);

    }

    public static void main(String[] args) {

        aa jIcon = new aa();

    }

}

方式二：

package com.swing.test;

import java.awt.Image;

import java.awt.Toolkit;

import javax.swing.JFrame;

public class ImageA extends JFrame {

    public ImageA() {

        super("aa");

        this.show();

        this.setSize(200, 400);

    }

    public static void main(String [] args) {

        Toolkit kit = Toolkit.getDefaultToolkit();

        Image img = kit.getImage("aaa.gif");

        //JFrame frame = new JFrame();

        //frame.setIconImage(img);

        ImageA imageA = new ImageA();

        imageA.setIconImage(img);

    }

}