addEventListener

他就是为一个事件添加一个监听，比如鼠标单击， 键盘某个键被按下等
现在的程序都是事件驱动的， 也就是你必须要知道用户有哪些动作，才能只当要如何去处理，事件监听就是起到这个作用的

/**
* 处理鼠标事件
*
* @author Administrator
*/
public class MouseListenerDemo extends JFrame {
public MouseListenerDemo ( ) {
initComponents();
}

protected void initComponents() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(400, 400);
JTextArea textArea = new JTextArea();
textArea.setText("Press the mouse button...");

textArea.addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e ) {
System.out.println("MouseListenerDemo.mouseClicked");
}

public void mousePressed(MouseEvent e ) {
System.out.println("MouseListenerDemo.mousePressed");
}

public void mouseReleased(MouseEvent e ) {
System.out.println("MouseListenerDemo.mouseReleased"