/** * 窗体类 */public class Main {    public static void main(String[] args) {        MyFrame m1 = new MyFrame();            }}class MyFrame extends Frame{    public MyFrame(){        this.setTitle("My first software");        this.setSize(300,200);        this.setBackground(Color.yellow);        this.setResizable(false); //不允许调整窗体大小        this.setLocation(300,300);        this.setLayout(new FlowLayout()); //把窗体的默认布局设成"流水布局"                //在窗体上添加按钮        Button b1 = new Button("click me.1");        this.add(b1);        this.add(new Button("click me.2"));                this.setVisible(true);    }}

/** * Panel类（面板类），组件容器 */public class Main {    public static void main(String[] args) {        MyPanel m1 = new MyPanel();    }}class MyPanel extends Frame{    public MyPanel(){        this.setTitle("My first software");        this.setSize(600,400);        this.setBackground(Color.yellow);        this.setResizable(false); //不允许调整窗体大小        this.setLocation(300,300);        this.setLayout(new FlowLayout()); //把窗体的默认布局设成"流水布局"        addPanel();        this.setVisible(true);    }    public void addPanel(){ //Panel的布局默认是"流水布局"        Panel p1 = new Panel(); //创建面板对象        p1.setBackground(Color.GREEN);        p1.add(new Button("click me.1"));        p1.add(new Button("click me.2"));        p1.add(new Button("click me.3"));        this.add(p1); //把面板添加到窗体上    }}

/** * Toolkit类：用于将各种组件绑定到本地系统的工具包。 */public class Main {    public static void main(String[] args) {        MyToolkit m1 = new MyToolkit();    }}class MyToolkit extends Frame{    public MyToolkit(){        this.setTitle("My first software");        this.setSize(600,400);        this.setBackground(Color.yellow);                Toolkit t1 = Toolkit.getDefaultToolkit(); //获取工具对象        Dimension d1 = t1.getScreenSize(); //获取当前屏幕的尺寸        double w = d1.getWidth();        double h = d1.getHeight();        int x = (int)(w/2);        int y = (int)(h/2);        this.setLocation(x-300,y-200);                //设置窗体图标 (新建一个包，把图片放进去)        URL url = this.getClass().getClassLoader().getResource("pkg1/image/fish.jpg"); //写成pkg1.image.fish.jpg不可以        Image ima1 = t1.getImage(url);        this.setIconImage(ima1);                this.setResizable(false); //不允许调整窗体大小        this.setLayout(new FlowLayout()); //把窗体的默认布局设成"流水布局"                this.setVisible(true);    }}