exercise15_1.java

一款用java编写的小型数据库管理系统

import javax.swing.*;
import java .awt.*;
import java.awt.event.*;
public class Exercise15_1 extends JFrame{
	private JLabel jlNumber1=new JLabel("Number1");
	private JLabel jlNumber2=new JLabel("Number2");
	private JLabel jlResult=new JLabel("Result");
	private JTextField jtNumber1=new JTextField(5);
	private JTextField jtNumber2=new JTextField(5);
	private JTextField jtResult=new JTextField(5);
    private JButton jb=new JButton("Divide");
    private JPanel jp1=new JPanel();
    private JPanel jp2=new JPanel();
    private int n1,n2,n3;
    public Exercise15_1(){
      	 jp1.setLayout(new GridLayout(1,1));
       	 jp1.add(jb);
        
       	 jp2.setLayout(new FlowLayout());
       	 jp2.add(jlNumber1);
       	 jp2.add(jtNumber1);
       	 jp2.add(jlNumber2);
       	 jp2.add(jtNumber2);
       	 jp2.add(jlResult);
       	 jtResult.setEditable(false);   	 
       	 jp2.add(jtResult);
       	 
       	 add(jp2,BorderLayout.NORTH);
       	 add(jp1,BorderLayout.SOUTH);
       	 
       	 jb.addActionListener(new ActionListener(){
       		public void actionPerformed(ActionEvent e){
       			try{
       				n1=Integer.parseInt(jtNumber1.getText());
       				n2=Integer.parseInt(jtNumber2.getText());
       				n3=n1/n2;
       				jtResult.setText(""+n3);
       			}
       			catch (ArithmeticException ex){
       				//用消息对话框来显示出错信息，２代表图标为警告符
       				JOptionPane.showMessageDialog(null,"Arithmetic errors","Warning",2);  
       			}
       			catch(IllegalArgumentException ex){
       				JOptionPane.showMessageDialog(null,"Number format errors","Warning",2);
       			}
       		}
       	 });
         }
    public static void main(String[]a){
    	Exercise15_1 frame=new Exercise15_1();
    	frame.setTitle("Exercise15_1");
    	frame.setLocationRelativeTo(null);   //居中显示
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }
}