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，圆形，五角星，并可以选择形状的颜色。Java代码

以下是一个简单的Java Swing实现绘图工具的代码示例：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
 
public class DrawingTool extends JFrame {
    private JPanel canvas;          // 绘图区域
    private Color color = Color.BLACK;  // 当前绘图颜色
    private int startX, startY;     // 起点坐标
    private int endX, endY;         // 终点坐标
    private int shapeType = 0;      // 当前绘图类型（0：直线，1：椭圆，2：矩形，3：圆形，4：五角星）
 
    public DrawingTool() {
        // 初始化窗口界面
        setTitle("绘图工具");
        setSize(800, 600);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
        // 创建工具栏
        JToolBar toolBar = new JToolBar();
        toolBar.setFloatable(false);
 
        // 创建颜色选择工具
        final JButton colorBtn = new JButton();
        colorBtn.setBackground(color);
        colorBtn.setPreferredSize(new Dimension(20, 20));
        colorBtn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                color = JColorChooser.showDialog(null, "选择颜色", color);
                colorBtn.setBackground(color);
            }
        });
        toolBar.add(colorBtn);
 
        // 创建绘图类型选择工具
        ButtonGroup shapeGroup = new ButtonGroup();
 
        JToggleButton lineBtn = new JToggleButton("直线");
        lineBtn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                shapeType = 0;
            }
        });
        shapeGroup.add(lineBtn);
        toolBar.add(lineBtn);
 
        JToggleButton ovalBtn = new JToggleButton("椭圆");
        ovalBtn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                shapeType = 1;
            }
        });
        shapeGroup.add(ovalBtn);
        toolBar.add(ovalBtn);
 
        JToggleButton rectBtn = new JToggleButton("矩形");
        rectBtn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                shapeType = 2;
            }
        });
        shapeGroup.add(rectBtn);
        toolBar.add(rectBtn);
 
        JToggleButton circleBtn = new JToggleButton("圆形");
        circleBtn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                shapeType = 3;
            }
        });
        shapeGroup.add(circleBtn);
        toolBar.add(circleBtn);
 
        JToggleButton starBtn = new JToggleButton("五角星");
        starBtn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                shapeType = 4;
            }
        });
        shapeGroup.add(starBtn);
        toolBar.add(starBtn);
 
        // 添加工具栏到窗口界面
        Container contentPane = getContentPane();
        contentPane.add(toolBar, BorderLayout.NORTH);
 
        // 创建绘图区域
        canvas = new JPanel() {
            // 重写paintComponent方法
            protected void paintComponent(Graphics g) {
                super.paintComponent(g);
                g.setColor(color);
                switch (shapeType) {
                    case 0:  // 直线
                        g.drawLine(startX, startY, endX, endY);
                        break;
                    case 1:  // 椭圆
                        g.drawOval(Math.min(startX, endX), Math.min(startY, endY), Math.abs(endX - startX), Math.abs(endY - startY));
                        break;
                    case 2:  // 矩形
                        g.drawRect(Math.min(startX, endX), Math.min(startY, endY), Math.abs(endX - startX), Math.abs(endY - startY));
                        break;
                    case 3:  // 圆形
                        g.drawOval(Math.min(startX, endX), Math.min(startY, endY), Math.abs(endX - startX), Math.abs(endY - startY));
                        break;
                    case 4:  // 五角星
                        int[] xPoints = {startX, startX+40, startX+10, startX+25, startX+40, startX, startX-40, startX-25, startX-10, startX-40};
                        int[] yPoints = {startY-40, startY-40, startY-10, startY+25, startY+40, startY+10, startY+40, startY+25, startY-10, startY-40};
                        g.drawPolygon(xPoints, yPoints, 10);
                        break;
                }
            }
        };
        canvas.addMouseListener(new MouseAdapter() {
            public void mousePressed(MouseEvent e) {
                startX = e.getX();
                startY = e.getY();
                endX = startX;
                endY = startY;
            }
        });
        canvas.addMouseMotionListener(new MouseMotionAdapter() {
            public void mouseDragged(MouseEvent e) {
                endX = e.getX();
                endY = e.getY();
                canvas.repaint();
            }
        });
        contentPane.add(canvas, BorderLayout.CENTER);
    }
 
    public static void main(String[] args) {
        DrawingTool tool = new DrawingTool();
        tool.setVisible(true);
    }
}

这个示例代码中主要实现了绘图工具的界面、绘图功能、拉橡皮筋功能、颜色选择功能和绘图类型选择功能。具体实现细节可以根据具体需求进行调整。