java GUI little exercise

Classroom teachers to students to practice
because it is the first time they used the way the programming GUI, it is relatively simple, but the idea is fairly clear, including the knowledge or many, that is not easy, it is uploaded to your reference

// window design
AveFrame .java

import java.awt.*;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

public  class AveFrame extends Frame{    
	TextArea textarea1= new TextArea();
	TextArea textarea2= new TextArea();
	
	public  AveFrame(String s) {
		super(s);
		setSize(500,300);
		init();
		setVisible(true);
		addWindowListener(new WindowAdapter()		//关闭窗口
        {  public void windowClosing(WindowEvent e)
           {  System.exit(0);
           }
        }
       );
		validate();
	}
	void init() {
		GridLayout grid=new GridLayout(1,2);
		setLayout(grid);
		//设置字体
		textarea1.setFont(new Font("黑体",0,22));
		textarea2.setFont(new Font("黑体",0,22));
		add(textarea1);
		add(textarea2);
		MyKeyListener myKeyListener = new MyKeyListener();//创建一个键盘监听事件对象
		textarea1.addKeyListener(myKeyListener);//添加myKeyListener键盘监听事件
	}
	class MyKeyListener  implements KeyListener{
		public void keyTyped(KeyEvent e) {
		}
		public void keyPressed(KeyEvent e) {
			int keyCode = e.getKeyCode();//获取所按键盘的键盘编码
			if (keyCode == KeyEvent.VK_ENTER) {
				Work work=new Work(textarea1.getText());
				textarea2.append(Double.toString(work.Ave()));
			}
		}
		public void keyReleased(KeyEvent e) {
		}
	}

// calculation process
work.java

public class Work {
	int sum=0;
	int ave=0;
	String str="";
	Work(String str){
		this.str=str;
		
	}
	public int Ave() {
		String regex="\\s+";
		String words[]=str.split(regex);
		for(int i=0;i<words.length;i++) {
			sum+=Double.parseDouble(words[i]);
		}
		ave=sum/words.length;
		return ave;
	}

The main program
testmain.java

public class testmain {
	public static void main(String args[]){
		new AveFrame("计算");
	}
}