java画图_Java实现的简单画图板示例

以下是一个简单的Java画图板示例：

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

public class SimplePaint extends JFrame implements MouseListener, MouseMotionListener {

    private int x1, y1, x2, y2;
    private Graphics g;
    private JPanel panel;

    public SimplePaint() {
        super("Simple Paint");
        setDefaultCloseOperation(EXIT_ON_CLOSE);

        panel = new JPanel();
        panel.addMouseListener(this);
        panel.addMouseMotionListener(this);
        getContentPane().add(panel);

        setSize(300, 300);
        setVisible(true);

        g = panel.getGraphics();
    }

    public void mousePressed(MouseEvent e) {
        x1 = e.getX();
        y1 = e.getY();
    }

    public void mouseDragged(MouseEvent e) {
        x2 = e.getX();
        y2 = e.getY();
        g.drawLine(x1, y1, x2, y2);
        x1 = x2;
        y1 = y2;
    }

    public void mouseMoved(MouseEvent e) {}
    public void mouseClicked(MouseEvent e) {}
    public void mouseEntered(MouseEvent e) {}
    public void mouseExited(MouseEvent e) {}
    public void mouseReleased(MouseEvent e) {}

    public static void main(String[] args) {
        new SimplePaint();
    }
}

这个示例使用了Java的Swing库来创建一个画图板。用户可以在画板上拖动鼠标来画线条。在这个示例中，我们使用了JPanel类来创建画板，并添加了鼠标事件监听器来处理用户的输入。我们还使用了Graphics类来绘制线条。