dividebyzerotest.java

例外处理当除数为0的情况

import java.text.DecimalFormat;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class DivideByZeroTest extends JFrame implements ActionListener
{
	private JTextField input1,input2,output;
	private int number1,number2;
	private double result;
	
	public DivideByZeroTest()
	{
		super("Demonstrating Exception");
		
		Container c=getContentPane();
		c.setLayout(new GridLayout(3,2));
		
		c.add(new JLabel("第一个数",SwingConstants.RIGHT));
		input1=new JTextField(10);
		c.add(input1);
		
		c.add(new JLabel("第二个数",SwingConstants.RIGHT));
		input2=new JTextField(10);
		c.add(input2);
		input2.addActionListener(this);//第二个文本域注册了ActionListener事件的监听器
		
		c.add(new JLabel("结果",SwingConstants.RIGHT));
		output=new JTextField();
		c.add(output);
		
		setSize(425,100);
		show();
	}	
	
	public void actionPerformed(ActionEvent e)//对应ActionEvent事件的方法
	{
		DecimalFormat precision3=new DecimalFormat("0.000");
		
		output.setText("这里可以得到结果哦");
		
		try
		{
			number1=Integer.parseInt(input1.getText());
			number2=Integer.parseInt(input2.getText());
			
			result=quotient(number1,number2);
			output.setText(precision3.format(result));
		}
		catch(NumberFormatException nfe)//捕获数据类型错误
		{
			JOptionPane.showMessageDialog(this,
			"你需要输入正确的数字",
			"数字类型错误",
			JOptionPane.ERROR_MESSAGE);
		}
		catch(DivideByZeroException dbze)//捕获自定义除数为零的错误
		{
			JOptionPane.showMessageDialog(this,
			dbze.toString(),"除数为零，请修改",
			JOptionPane.ERROR_MESSAGE);
		}
	}
	
	public double quotient(int numberator,int denominator) throws DivideByZeroException
	{
		if(denominator==0)
		{
			throw new DivideByZeroException();
		}
		return (double) numberator/denominator;
	}
	
	public static void main(String[] args)
	{
		DivideByZeroTest app=new DivideByZeroTest();
		//给窗口注册WindowListener事件,用到了一个匿名类进行事件处理
		//匿名类里面是实现了一个适配器接口
		
		app.addWindowListener(new WindowAdapter()
		                      {
		                      	public void windowClosing(WindowEvent e)
		                      	{
		                      		e.getWindow().dispose();
		                      		System.exit(0);
		                      	}
		                      }
		                  );
	}
}