窗口

import javax.swing.*;import java.awt.*;import java.awt.event.InputEvent; import java.awt.event.KeyEvent;public class MenuCode1 {public static void main(String[] args) {   JFrame win =new JFrame("浏览器");      //创建并添加菜单栏   JMenuBar menubar =new JMenuBar();   win.setJMenuBar(menubar);      //创建各项菜单，并且   JMenu menufile=new JMenu("文件(F)"),   menuEdit =new JMenu("编辑(E)"),   menuView =new JMenu ("查看(V)");         menufile.setMnemonic('F');      menuEdit.setMnemonic('E');      menuView.setMnemonic('V');      menubar.add(menufile);      menubar.add(menuEdit);      menubar.add(menuView);            //添加各个菜单项      JMenu itemOpen =new JMenu("打开");       itemOpen.setMnemonic('O');       JMenuItem item1=new JMenuItem("打开x");       JMenuItem item2 =new JMenuItem ("打开y");       itemOpen.add(item1);       itemOpen.add(item2);      JMenu itemSave=new JMenu("保存");      itemSave.setMnemonic('S');    //  itemSave.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_S,InputEvent.CTRL_MASK));       //这句什么？？、      menufile.add(itemOpen);      menufile.add(itemSave);      //添加编辑      JMenu itemCopy =new JMenu("复制");     // itemCopy.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_C,InputEvent.CTRL_MASK));      menuEdit.add(itemCopy);      //添加查看      JMenu itemStop=new JMenu("停止");      JMenu itemRefresh =new JMenu("刷新");    //  itemStop.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_S,InputEvent.CTRL_MASK));    //  itemRefresh.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_R,InputEvent.CTRL_MASK));      menuView.add(itemStop);      menuView.add(itemRefresh);      win.setSize(300,400);      win.setLocation(200, 200);      win.setVisible(true);                  win.validate();      win.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);}}