哥java学识有大进 干回之前的小学生系统像切菜一样简单 不说了 来代码

package runok;
import java.util.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.*;
public class vv extends JFrame implements ActionListener{

/**
* 作者：范铭祥
* 功能：一个简单的小学生四则运算 自动 生成系统
*/
JPanel jp1,jp2,jp3;
JLabel jlb1,jlb2;
JButton jb1;
JTextField jtf1,jtf2;
JTextArea ee;
public double w1;
public double m1;
String fh;
public static void main(String[] args) 
{
  vv start=new vv();
}
public vv()
{
    jp1=new JPanel();
    jp2=new JPanel();
    jp3=new JPanel();
    
    jlb1=new JLabel("题目");
    jlb2=new JLabel("你的答案:");

    jb1=new JButton("判断答案");
    jb1.addActionListener(this);
    jb1.setActionCommand("aa");
    JTextArea txtArea = new JTextArea(1,15);
    jtf2=new JTextField(20);
   ee = new JTextArea(1,10);
    //设置布局管理
    this.setLayout(new GridLayout(3,1));
    //加入各个组件
    jp1.add(jlb1);
    jp1.add(txtArea);
    
    jp2.add(jlb2);
    jp2.add(jtf2);
    jp3.add(jb1);
    jp3.add(ee);
    //加入到JFrame
    this.add(jp1);
    this.add(jp2);
    this.add(jp3);
//在这里用yy方法来获取题目 w 符号 m
    yy tt=new yy();

    
    w1=tt.ret1();
    m1=tt.ret2();
    fh=tt.ret3();
    txtArea.append(w1+fh+m1);
    this.setSize(400, 250);
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    this.setVisible(true);
}
public void yes()
{ ee.append("正确！");    }
public void no()
{ee.append("错误！");}
public void cc()
{
    int answer=(int) (Double.parseDouble(jtf2.getText()));;
        if(fh.equals("+"))
        {
            if(answer==w1+m1){
                yes();
            }else{
                no();
            }        
        }
        if(fh.equals("-"))
        {
                if(answer==w1-m1){
                    yes();
                }else{
                    no();
                }        
        }
        if(fh.equals("*"))
        {
                if(answer==w1*m1){
                   yes();
                }else{
                   no();
                }        
        }
        if(fh.equals("/"))
        {
                if(answer==w1/m1){
                    yes();
                }else{
                    no();
                }        
        }        
}
@Override
public void actionPerformed(ActionEvent e) 
    {
    // !!!!
    if(e.getActionCommand()=="aa")
    {
        cc();
    }
    }

}


class yy
{
    private int max=4;
    private int min=1;
    private double w2,m2;
    private String ff;
    Random random = new Random();

    //System.out.println(s); 
    public yy()
    {
    int s = random.nextInt(max)%(max-min+1) + min;

    double x=random.nextInt(max-2)%(max-2-min+1) + min;
 
    double y=random.nextInt(max-1)%(max-1-min+1) + min;
    int y1up=(int) Math.pow(10,x);
    int y1dn=(int) Math.pow(10,x-1);
    int y2up=(int) Math.pow(10,y);
    int y2dn=(int) Math.pow(10,y-1);
    int x_y1=random.nextInt(y1up)%(y1up-y1dn+1) + y1dn;
    int x_y2=random.nextInt(y2up)%(y2up-y2dn+1) + y2dn;
    double w=(double)x_y1;
    double m=(double)x_y2;
    this.w2=w;
    this.m2=m;
    switch(s)
    {
    case 1:
    {
    this.ff="+"; 
    System.out.println(w+"+"+m+"=" );
    break;
    }
    case 2:
    {
    this.ff="-";
    System.out.println(w+"-"+m+"=" );
    break;
    }
    case 3:
    {
    this.ff="*";
    System.out.println(w+"*"+m+"=" );
    break;
    }
    case 4:
    {
    this.ff="/";
    System.out.println(w+"/"+m+"=" );
    break;
    }

    }
    }
    public double ret1()
    {
        return w2;
    }
    public double ret2()
    {
        return m2;
    }
    public String ret3()
    {
        return ff;
    }
}