scoreexceptiondemo.java

java课程的资料以及实验的代码

import java.awt.Frame;
import java.awt.Button;
import java.awt.GridLayout;
import java.awt.Label;
import java.awt.Panel;
import java.awt.TextField;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.BorderLayout;
class ScoreException extends Exception
{
	public ScoreException()
	{
		super("Score is incorrect");
	}
	public String toString()
	{
		return "The score must between 0 and 100";
	}
}
public class ScoreExceptionDemo extends Frame{
	Label lbl1;
	Label lbl2;
	Button btn1;
    Button btn2;
    TextField tf1;
	/**
	 * @param args
	 */
    public ScoreExceptionDemo()
    {
    	lbl1=new Label("Score");
    	tf1=new TextField(20);
    	
    	lbl2=new Label("    ");
    	btn1=new Button("ok");
    	btn2=new Button("canel");
    	Panel p1=new Panel();
    	p1.setLayout(new GridLayout(2,2));
    	p1.add(lbl1);
    	p1.add(tf1);
    	p1.add(btn1);
    	p1.add(btn2);
    	this.add(p1,BorderLayout.CENTER);
    	this.add(lbl2,BorderLayout.SOUTH);
    	btn1.addActionListener(new ActionListener()
    	{
    		public void actionPerformed(ActionEvent ae)
    		{
    		try
    		{  
    			int num=Integer.parseInt(tf1.getText());
    			lbl2.setText(new Integer(checkNUmber(num)).toString());
    		}
    		catch(ScoreException se)
    		{
    			lbl2.setText(se.toString());
    		}
    		}
    	});
    	btn2.addActionListener(new ActionListener()
    	{
    		public void actionPerformed(ActionEvent ae)
    		{
    		System.exit(0);
    		}
    	});
    	this.setSize(260,200);
    	this.setVisible(true);
    }
    public int checkNUmber(int num) throws ScoreException
    {
    	if(num<0 || num>100)
    	throw new ScoreException();
    	return num;
    }
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		
      new  ScoreExceptionDemo();
	}

}