e1610.java

java小程序

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.lang.*;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
public class E1610 extends JApplet 
{
private Container c;
private JLabel label1,label2;
private JTextField text1,text2;
public void init()
{
c=getContentPane();
MyListener myListener=new MyListener();
label1=new JLabel("输入摄氏温度：");
label2=new JLabel("转换后的华氏温度");
text1=new JTextField("",10);
text1.addKeyListener(myListener);
text2=new JTextField("32",10);
c.setLayout(new FlowLayout());
c.add(label1);
c.add(text1);
c.add(label2);
c.add(text2);
}

class MyListener extends KeyAdapter
{
public void keyReleased(KeyEvent e)
{
String str,str1;
Double Sheshi,Huashi;
str=text1.getText();
if(str.equals(""))
str="0";
if(!isNumeric(str))
JOptionPane.showMessageDialog(null,"请输入一个数字","输入信息",JOptionPane.WARNING_MESSAGE);
Sheshi=Double.parseDouble(str);
Huashi=Sheshi*9/5.0+32;
str1=String.valueOf(Huashi);
text2.setText(str1);
}

public boolean isNumeric(String str)
{
Pattern pattern = Pattern.compile("[0-9]*");
Matcher isNum = pattern.matcher(str);
if(isNum.matches()==false )
return false;
else
return true;
}
}
}