本程序的功能是监听对于菜单项和工具条按钮的操作。主窗口中有菜单、工具条和一个文字标签，菜单中有“文件”项，“文件”菜单中包括菜单项“新建”、“保存”、“打印”、“页面设置”和“退出”，工具条上包括按钮“新建”、“保存”、“打印”、“页面设置”和“退出”。单击任何一个菜单项或任何一个工具条按钮，文字标签都会显示哪个构件被选中。请更正题中带下划线的部分。运行结果如下图所示。
注意：不改变程序的结构，不得增行或删行。
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class advance extends JFrame
private JLabel actionlnfo;
public advance(String titleText)
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
super(titleText);
actionInfo=new JLabel("事件信息");
JToolBar tb=new JTooBar();
Menu file=new Menu( "文件" );
JMenuBar mb=new JMenuBar();
mb.add(file);
NewAction na=new NewAction(actionInfo);
file.add(na);
tb.add(na);
SaveAction sa=new SaveAction(actionInfo);
file.add(sa);
tb.add(sa);
PrintAction pta=new PrintAction(actionInfo);
file.add(pra);
tb.add(pra);
PageSetAction psa=new PageSetAction(actionInfo);
file.add(psa);
tb.add(psa);
ExitAction ea=new ExitAction(actionInfo);
file.add(ea);
tb.add(ea);
setJMenuBar(mb);
Container cp=getContentPane();
cp.setLayout(new BorderLayout());
cp.add(tb);
cp.add(actionInfo, BorderLayout.CENTER );
setSize(350, 200);
setVisible(true);
public static void main(String[] args)
new advance("advance");
class NewAction extends AbstractAction
JLabel label;
public NewAction(JLabel label)
super("新建");
this.label=label;
public void actionPerformed(ActionEvent e)
label.setText("您选择了新建");
class SaveAction extends AbstractAction
JLabel label;
public SaveAction(JLabel label)
super("保存");
this.label=label;
public void actionPerformed(ActionEvent e)
label.setText ("您选择了保存");
class printAction extends AbstractAction
JLabel label;
public PrintAction(JLabel label)
super("打印");
this.label=label;
public void actionPerformed(ActionEvent e)
label.setText ("您选择了打印");
class PageSetAction extends AbstractAction
JLabel label;
public pageSetAction(JLabel label)
super("页面设置");
this.label=label;
public void actionPerformed(ActionEvent e)
label.setText("您选择了页面设置");
class ExitAction extends AbstractAction
JLabel label;
public ExitAction(JLabel label)
super("退出");
this.label=label;
public void actionPerformed(ActionEvent e)
label.setText ("您选择了退出");
