编写程序在窗体上输出如下图形。 * ** *** **** java

您可以使用以下代码在窗体上输出如下图形：

public class PrintTriangle extends JFrame {
    public PrintTriangle() {
        setTitle("Print Triangle");
        setSize(300, 200);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        add(new TrianglePanel());
    }

    public static void main(String[] args) {
        PrintTriangle frame = new PrintTriangle();
        frame.setVisible(true);
    }
}

class TrianglePanel extends JPanel {
    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        int x = 10;
        int y = 30;
        for (int i = 1; i <= 4; i++) {
            for (int j = 1; j <= i; j++) {
                g.drawString("*", x, y);
                x += 10;
            }
            x = 10;
            y += 20;
        }
        g.drawString("java", x, y);
    }
}