实现一个绘图工具，可以按拉橡皮筋的方法绘制直线，椭圆，矩形，并可以选择形状的颜色java代码

以下是一个简单的Java代码示例，实现了一个绘图工具，可以按拉橡皮筋的方法绘制直线、椭圆、矩形，并可以选择形状的颜色：

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

public class DrawingTool extends JFrame {
    private int startX, startY, endX, endY;
    private Color currentColor = Color.BLACK;
    private String currentShape = "Line";

    public DrawingTool() {
        super("Drawing Tool");
        setSize(800, 600);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel drawingPanel = new JPanel();
        drawingPanel.setBackground(Color.WHITE);
        drawingPanel.addMouseListener(new MouseAdapter() {
            public void mousePressed(MouseEvent e) {
                startX = e.getX();
                startY = e.getY();
            }
        });
        drawingPanel.addMouseMotionListener(new MouseAdapter() {
            public void mouseDragged(MouseEvent e) {
                endX = e.getX();
                endY = e.getY();
                repaint();
            }
        });
        drawingPanel.addMouseListener(new MouseAdapter() {
            public void mouseReleased(MouseEvent e) {
                endX = e.getX();
                endY = e.getY();
                repaint();
            }
        });

        JPanel controlPanel = new JPanel();
        controlPanel.setLayout(new FlowLayout());

        JButton colorButton = new JButton("Choose Color");
        colorButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                currentColor = JColorChooser.showDialog(null, "Choose Color", currentColor);
            }
        });
        controlPanel.add(colorButton);

        JRadioButton lineButton = new JRadioButton("Line", true);
        lineButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                currentShape = "Line";
            }
        });
        controlPanel.add(lineButton);

        JRadioButton ovalButton = new JRadioButton("Oval");
        ovalButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                currentShape = "Oval";
            }
        });
        controlPanel.add(ovalButton);

        JRadioButton rectButton = new JRadioButton("Rectangle");
        rectButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                currentShape = "Rectangle";
            }
        });
        controlPanel.add(rectButton);

        ButtonGroup shapeGroup = new ButtonGroup();
        shapeGroup.add(lineButton);
        shapeGroup.add(ovalButton);
        shapeGroup.add(rectButton);

        add(drawingPanel, BorderLayout.CENTER);
        add(controlPanel, BorderLayout.SOUTH);
        setVisible(true);
    }

    public void paint(Graphics g) {
        super.paint(g);
        Graphics2D g2d = (Graphics2D) g;
        g2d.setColor(currentColor);
        if (currentShape.equals("Line")) {
            g2d.drawLine(startX, startY, endX, endY);
        } else if (currentShape.equals("Oval")) {
            int width = Math.abs(endX - startX);
            int height = Math.abs(endY - startY);
            int x = Math.min(startX, endX);
            int y = Math.min(startY, endY);
            g2d.drawOval(x, y, width, height);
        } else if (currentShape.equals("Rectangle")) {
            int width = Math.abs(endX - startX);
            int height = Math.abs(endY - startY);
            int x = Math.min(startX, endX);
            int y = Math.min(startY, endY);
            g2d.drawRect(x, y, width, height);
        }
    }

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

这段代码使用JFrame作为窗口，使用JPanel作为绘图区域，使用鼠标事件来实现按拉橡皮筋的方法绘制直线、椭圆、矩形，使用JColorChooser类实现颜色选择器。注意，在paint方法中需要使用Graphics2D类来绘制图形，并且需要根据当前选择的形状来绘制不同的图形。