利用Java设计绘图版，可以绘画在界面设定位置和大小的直线、空心椭圆或者实心椭圆、空心矩形或者实心矩形和多边形

好的，下面是一个稍微复杂一点的利用Java设计绘图板的示例，可以绘制直线、空心椭圆或者实心椭圆、空心矩形或者实心矩形和多边形。示例代码如下：

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

public class DrawBoard extends JFrame {
    private DrawPanel drawPanel;
    private JPanel toolPanel;
    private JButton lineBtn, ovalBtn, rectBtn, polyBtn;
    private JComboBox<String> thicknessBox;
    private JLabel statusLabel;
    private int startX, startY, endX, endY;
    private int shapeType = 0;
    private int thickness = 1;
    private boolean isFilled = false;

    private enum ShapeType {
        LINE, OVAL, RECT, POLY
    }

    public DrawBoard() {
        setTitle("绘图板");
        setSize(600, 500);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(new BorderLayout());

        // 工具面板
        toolPanel = new JPanel();
        toolPanel.setLayout(new FlowLayout(FlowLayout.LEFT));
        lineBtn = new JButton("直线");
        ovalBtn = new JButton("椭圆");
        rectBtn = new JButton("矩形");
        polyBtn = new JButton("多边形");
        thicknessBox = new JComboBox<String>(new String[] {"1", "2", "3", "4", "5"});
        statusLabel = new JLabel("就绪");
        toolPanel.add(lineBtn);
        toolPanel.add(ovalBtn);
        toolPanel.add(rectBtn);
        toolPanel.add(polyBtn);
        toolPanel.add(new JLabel("线宽："));
        toolPanel.add(thicknessBox);
        toolPanel.add(statusLabel);
        add(toolPanel, BorderLayout.NORTH);

        // 绘图面板
        drawPanel = new DrawPanel();
        add(drawPanel, BorderLayout.CENTER);

        // 直线按钮事件
        lineBtn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                shapeType = ShapeType.LINE.ordinal();
                statusLabel.setText("绘制直线");
            }
        });

        // 椭圆按钮事件
        ovalBtn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                shapeType = ShapeType.OVAL.ordinal();
                statusLabel.setText("绘制椭圆");
            }
        });

        // 矩形按钮事件
        rectBtn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                shapeType = ShapeType.RECT.ordinal();
                statusLabel.setText("绘制矩形");
            }
        });

        // 多边形按钮事件
        polyBtn.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                shapeType = ShapeType.POLY.ordinal();
                statusLabel.setText("绘制多边形");
            }
        });

        // 线宽下拉框事件
        thicknessBox.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                thickness = thicknessBox.getSelectedIndex() + 1;
            }
        });

        // 鼠标事件
        drawPanel.addMouseListener(new MouseAdapter() {
            public void mousePressed(MouseEvent e) {
                startX = e.getX();
                startY = e.getY();
            }

            public void mouseReleased(MouseEvent e) {
                endX = e.getX();
                endY = e.getY();
                drawShape(startX, startY, endX, endY, shapeType, thickness, isFilled);
                statusLabel.setText("就绪");
            }
        });

        // 多边形绘制事件
        drawPanel.addMouseMotionListener(new MouseMotionAdapter() {
            public void mouseDragged(MouseEvent e) {
                if (shapeType == ShapeType.POLY.ordinal()) {
                    drawPanel.setTempPoint(e.getX(), e.getY());
                    drawPanel.repaint();
                }
            }
        });

        setVisible(true);
    }

    private void drawShape(int x1, int y1, int x2, int y2, int shapeType, int thickness, boolean isFilled) {
        Graphics2D g2d = (Graphics2D) drawPanel.getGraphics();
        g2d.setStroke(new BasicStroke(thickness));
        g2d.setColor(Color.BLACK);
        if (shapeType == ShapeType.LINE.ordinal()) {
            g2d.drawLine(x1, y1, x2, y2);
        } else if (shapeType == ShapeType.OVAL.ordinal()) {
            if (isFilled) {
                g2d.fillOval(Math.min(x1, x2), Math.min(y1, y2), Math.abs(x2 - x1), Math.abs(y2 - y1));
            } else {
                g2d.drawOval(Math.min(x1, x2), Math.min(y1, y2), Math.abs(x2 - x1), Math.abs(y2 - y1));
            }
        } else if (shapeType == ShapeType.RECT.ordinal()) {
            if (isFilled) {
                g2d.fillRect(Math.min(x1, x2), Math.min(y1, y2), Math.abs(x2 - x1), Math.abs(y2 - y1));
            } else {
                g2d.drawRect(Math.min(x1, x2), Math.min(y1, y2), Math.abs(x2 - x1), Math.abs(y2 - y1));
            }
        } else if (shapeType == ShapeType.POLY.ordinal()) {
            int[] xPoints = drawPanel.getxPoints();
            int[] yPoints = drawPanel.getyPoints();
            int nPoints = drawPanel.getNumPoints();
            if (isFilled) {
                g2d.fillPolygon(xPoints, yPoints, nPoints);
            } else {
                g2d.drawPolygon(xPoints, yPoints, nPoints);
            }
        }
        g2d.dispose();
    }

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

class DrawPanel extends JPanel {
    private int[] xPoints;
    private int[] yPoints;
    private int numPoints;
    private int tempX, tempY;

    public DrawPanel() {
        setBackground(Color.WHITE);
        setVisible(true);
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        if (numPoints > 0) {
            g.drawPolyline(xPoints, yPoints, numPoints);
        }
        if (tempX != 0 && tempY != 0) {
            g.drawLine(xPoints[numPoints - 1], yPoints[numPoints - 1], tempX, tempY);
        }
    }

    public void setTempPoint(int x, int y) {
        tempX = x;
        tempY = y;
        repaint();
    }

    public int[] getxPoints() {
        return xPoints;
    }

    public int[] getyPoints() {
        return yPoints;
    }

    public int getNumPoints() {
        return numPoints;
    }

    public void addPoint(int x, int y) {
        if (numPoints == 0) {
            xPoints = new int[100];
            yPoints = new int[100];
        }
        xPoints[numPoints] = x;
        yPoints[numPoints] = y;
        numPoints++;
    }

    public void clearPoints() {
        numPoints = 0;
        tempX = 0;
        tempY = 0;
        repaint();
    }
}

这个示例中，工具面板包括直线、椭圆、矩形和多边形四个按钮，以及线宽下拉框和状态栏。绘图面板包括一个鼠标事件监听器和一个多边形绘制事件监听器。在鼠标事件监听器中，根据当前选择的形状类型、线宽和是否填充来绘制直线、椭圆或矩形。在多边形绘制事件监听器中，根据鼠标移动的轨迹来绘制多边形。

您可以根据自己的需求和能力进行修改和扩展，例如添加更多的图形类型、颜色选择、撤销操作等等，使得绘图板更加实用和方便。