java课程设计，随机点名器

package sdju.edu.renzhiwei; import java.awt.*; import javax.swing.*; class MyFrame extends JFrame{ JMenuBar menuBar; JMenu fileMenu,setMenu,color; JMenuItem openItem,exitItem; JRadioButtonMenuItem blackItem,blueItem,goldItem,greenItem,redItem; JSplitPane split; public MyFrame(String s){ super(s); this.setSize(450,550); this.setLocationRelativeTo(null); split = new JSplitPane(JSplitPane.VERTICAL_SPLIT); setContentPane(split); //按钮放在窗口下面 JButton ranBut = new JButton("随机点名"); ranBut.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR )); split.add(ranBut,JSplitPane.RIGHT); ranBut.addActionListener(new UpdateXls()); //设置标签 Font font = new Font("华文彩云",Font.BOLD,80); JLabel lab = new JLabel("欢迎使用",SwingConstants.CENTER); lab.setFont(font); split.add(lab,JSplitPane.LEFT); split.setDividerLocation(430); //菜单的组件和放置 menuBar = new JMenuBar(); fileMenu = new JMenu("文件"); setMenu = new JMenu("设置"); color = new JMenu("写入字体颜色"); blackItem = new JRadioButtonMenuItem("黑色",true); blueItem = new JRadioButtonMenuItem("蓝色"); goldItem = new JRadioButtonMenuItem("金色"); greenItem = new JRadioButtonMenuItem("绿色"); redItem = new JRadioButtonMenuItem("红色"); ButtonGroup grp = new ButtonGroup(); grp.add(blackItem); grp.add(blueItem); grp.add(goldItem); grp.add(greenItem); grp.add(redItem); color.add(blackItem); color.add(blueItem); color.add(goldItem); color.add(greenItem); color.add(redItem); setMenu.add(color); blackItem.addActionListener(new ColorXls(this)); blueItem.addActionListener(new ColorXls(this)); goldItem.addActionListener(new ColorXls(this)); greenItem.addActionListener(new ColorXls(this)); redItem.addActionListener(new ColorXls(this)); openItem = new JMenuItem("打开"); exitItem = new JMenuItem("退出"); fileMenu.add(openItem); fileMenu.addSeparator(); fileMenu.add(exitItem); menuBar.add(fileMenu); menuBar.add(setMenu); this.setJMenuBar(menuBar); openItem.addActionListener(new ReadXls(this)); exitItem.addActionListener(new ReadXls(this)); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setVisible(true); } }