本文实例主要实现Java拖曳鼠标画线的功能，为了达到画线的功能，分别用implements MouseListener与MouseMotionListener，并且由mousePressed(),mouseReleased()取得鼠标拖曳的开始与结束坐标。这是一个掌握Java鼠标事件的很好的范例。

具体实现代码如下：

import java.awt.*; import java.awt.event.*; import javax.swing.*; public class MouseDemo extends JFrame implements MouseListener, MouseMotionListener { int flag; //flag=1代表Mouse Moved,flag=2代表Mouse Dragged int x = 0; int y = 0; int startx, starty, endx, endy;//起始坐标与终点坐标 public MouseDemo() { Container contentPane = getContentPane(); contentPane.addMouseListener(this); contentPane.addMouseMotionListener(this); setSize(300, 300); show(); addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent e) { System.exit(0); } }); } /*由mousePressed(),mouseReleased()取得鼠标拖曳的开始与结束坐标*/ public void mousePressed(MouseEvent e) { startx = e.getX(); starty = e.getY(); } public void mouseReleased(MouseEvent e) { endx = e.getX(); endy = e.getY(); } public void mouseEntered(MouseEvent e) { } public void mouseExited(MouseEvent e) { } public void mouseClicked(MouseEvent e) { } /*mouseMoved(),mouseDragged()取得鼠标移动的每一个坐标，并调用repaint()方法*/ public void mouseMoved(MouseEvent e) { flag = 1; x = e.getX(); y = e.getY(); repaint(); } public void mouseDragged(MouseEvent e) { flag = 2; x = e.getX(); y = e.getY(); repaint(); } public void update(Graphics g) { g.setColor(this.getBackground()); g.fillRect(0, 0, getWidth(), getHeight()); //清除当前的窗口内容 paint(g); } public void paint(Graphics g) { g.setColor(Color.black); if (flag == 1) { g.drawString("鼠标坐标：(" + x + "," + y + ")", 10, 50); g.drawLine(startx, starty, endx, endy); } if (flag == 2) { g.drawString("拖曳鼠标价坐标：(" + x + "," + y + ")", 10, 50); g.drawLine(startx, starty, x, y); } } public static void main(String[] args) { new MouseDemo(); } }

该程序在画线过程中，拖拽时会显示鼠标坐标。读者还可以根据自身需求对该程序进行修改和完善，使之更加具有实用性。