java程序设计基础教程第二版: 练习p225-1

import java.awt.*;import java.awt.event.*;import javax.swing.*;public class Unit8_p225_1 extends Frame {TextArea text2=new TextArea("",6,40);TextField text1=new TextField("",20);/** * @param args */public static void main(String[] args) {// TODO 自动生成方法存根Unit8_p225_1 f=new Unit8_p225_1();}Unit8_p225_1(){add(text1);add(text2);setVisible(true);setLayout(new FlowLayout());setBounds(100,100,400,400);text1.addActionListener(new ActionListener(){public void actionPerformed(ActionEvent e){try{if(Integer.parseInt(text1.getText())<1000){text2.append(text1.getText()+"/n");}if(Integer.parseInt(text1.getText())>=1000){int n=JOptionPane.showConfirmDialog(text1,"Word is over 1000 byte,Continue?","Do you sure?",JOptionPane.YES_NO_OPTION);if(n==JOptionPane.YES_OPTION){text2.append(text1.getText()+"/n");}else if(n==JOptionPane.NO_OPTION){}}}catch(Exception e3){text1.setText("Allowed Formet:number");}}});validate();}}