如何用java编写一个花名随机抽取器

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;

 private static JLabel jl= new JLabel("文件：");
 private static JTextField jt =new JTextField();
 private static JButton OpenButton =new JButton("选择文件");
 private static JTextField jt2 =new JTextField();//文本框 显示抽取名单
 private static JButton StartButton =new JButton("开始抽取");
 private static JLabel ClassjL= new JLabel("班级：");
 private static JTextField ClassjT =new JTextField();//显示班级
 private static JLabel NumjL= new JLabel("人数：");
 private static JTextField NumjT =new JTextField();//显示人数
 private static JLabel jl2= new JLabel("抽取模式：");
 private static JComboBox jc= new JComboBox();//下拉列表框
 private static JButton AboutButton =new JButton("关于");
 private static JOptionPane jo =new JOptionPane();//弹出一个提示框
 private static String[]s ;//用来存放人名
 private static Font font = new Font("宋体",Font.BOLD,18); //设置字体对象
 private static int Number=0;//用来存放抽取人数

    private void windows() {
     JFrame jf =new JFrame ("花狗抽取器  本人博客:fdogcsdn.com");
     jf.setIconImage(new ImageIcon("Icon.jpg").getImage());
     Container c=jf.getContentPane();
     c.setLayout(new GridLayout(4,2,10,10)); 
     OpenButton.setFocusPainted(false);
     StartButton.setFocusPainted(false);
     AboutButton.setFocusPainted(false);//去掉按钮文字旁边的虚线框
     JPanel jp1 =new JPanel();
     JPanel jp2 =new JPanel(new BorderLayout());
     JPanel jp3 =new JPanel();
     JPanel jp4 =new JPanel();//添加面板
     jt.setColumns(10);
     ClassjT.setColumns(6);
     NumjT.setColumns(4);
     jt2.setHorizontalAlignment(JTextField.CENTER);
     jc.addItem("--请选择--");
     jc.addItem("抽取一人");
     jc.addItem("抽取三人");
     jc.addItem("抽取五人");
     jp1.add(jl);
     jp1.add(jt);
     jp1.add(OpenButton);
     jp2.add(jt2,BorderLayout.CENTER);
     jp3.add(ClassjL);
     jp3.add(ClassjT);
     jp3.add(NumjL);
     jp3.add(NumjT);
     jp3.add(jl2);
     jp3.add(jc); 
     jp4.add(StartButton);
     jp4.add(AboutButton);
     c.add(jp1);
     c.add(jp2);
     c.add(jp3);
     c.add(jp4);
     jf.setVisible(true);
     jf.setBounds(800, 200, 400, 500);
     jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     getOpenButton(); //下面三个方法是用来监听按钮事件方法
     getAboutButton();
     getSrartButton();
    }

    private void getOpenButton() {
     OpenButton.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
          JFileChooser fc =new JFileChooser();//这个对象就是我们点击打开文件，出来的文件选择器
          fc.setCurrentDirectory(new File("."));//指定当前默认目录
          fc.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);//可以选择只打开文件或者文件夹
          fc.setMultiSelectionEnabled(false);//是否允许多选文件
          int i =fc.showOpenDialog(getContentPane());
          if(i==JFileChooser.APPROVE_OPTION) {//判断是否打开
           File file =fc.getSelectedFile();
           //显示选中内容
           jt.setText(fc.getSelectedFile().getName());
           try{
            FileReader fr =new FileReader(file);
            BufferedReader  in =new BufferedReader (fr);
            String line= in.readLine();//读取txt文件中的内容
            s =line.split(" ");//以空格为分隔符，存储人名
            NewMessage();   //监听事件
            getjcomboBox();//监听事件
           }catch(Exception e1) {
            e1.printStackTrace();
           }        
          }
      }
     });
    }

    private void getAboutButton() {
     AboutButton.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        jo.showMessageDialog(null, "可建立txt文件:\n写入班级名字然后空格学生名字\n名字和名字之间必须要用空格隔开\n即可识别班级名称和人数以及名单");
      }
     });
    }

    private void getjcomboBox() {
     jc.addItemListener(new ItemListener() {
      public void itemStateChanged(ItemEvent  e) {
       if(e.getStateChange() == ItemEvent.SELECTED) {
        String itemSize = (String) e.getItem();  
        if(itemSize=="抽取一人") {
         Number =1;
        }
        if(itemSize=="抽取三人") {
         Number =3;
        }
        if(itemSize=="抽取五人") {
         Number =5;
        }
       }
      }
     });
    }

   private void getSrartButton() {
     StartButton.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
       switch(Number) {
       case 1:
        int num1 =(int)1+(int)(Math.random()*(s.length-1-1));
        jt2.setText(s[num1]);
        break;
       case 3:
        int []num3=new int[100];
        for(int i=0;i<100;i++) {
         num3[i]=(int)1+(int)(Math.random()*(s.length-1-1));
        }
        for(int i=0;i<98;i++) {
         if(num3[i]!=num3[i+1] && num3[i]!=num3[i+2] && num3[i+1]!=num3[i+2]) {
             String strtext1= s[num3[i]]+" "+s[num3[i+1]]+" "+s[num3[i+2]];
             jt2.setText(strtext1);
          break;
         }
        }
        break;
       case 5:
        int []num5=new int[100];
        for(int i=0;i<100;i++) {
         num5[i]=(int)1+(int)(Math.random()*(s.length-1-1));
        }
        for(int i=0;i<95;i++) {
         if(num5[i]!=num5[i+1] && num5[i]!=num5[i+2] && num5[i]!=num5[i+3] && num5[i]!=num5[i+4]
         && num5[i+1]!=num5[i+2] && num5[i+1]!=num5[i+3] && num5[i+1]!=num5[i+4]
         &&num5[i+2]!=num5[i+3] && num5[i+2]!=num5[i+4]
         &&num5[i+3]!=num5[i+4]) {
             String strtext1= s[num5[i]]+" "+s[num5[i+1]]+" "+s[num5[i+2]]+" "+s[num5[i+3]]+" "+s[num5[i+4]];
             jt2.setText(strtext1);
          break;
         }
        }
        break;
       }
      }
     });
    }

    private void NewMessage() {
     ClassjT.setText(s[0]);
     String s1="";
     s1=""+(s.length-1);
     NumjT.setText(s1);
     jt2.setFont(font);
     jt2.setForeground(Color.blue);
     jt2.setText("已就绪，请开始抽取。");
    }

 public static void main(String[] args) {
  callmy call = new callmy();
  call.windows();
 }