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：
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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();
}
}
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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。