yuefen.java

200多个自己编的java程序,大家可以学一下.

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class Yuefen extends Applet implements ActionListener
{ TextField text1,text2;
  Button button;
  public void init()
  { text1=new TextField(5);
    text2=new TextField(12);
    button=new Button("确定");
    add(text1);  
    add(text2);
    text1.addActionListener(this);
  }
  public void paint(Graphics g)
  {
    g.drawString("在左边文本框输入一个1……12之间的数字并回车",10,100);
    g.drawString("右边文本框会显示对应的月份及天数",10,120 );
  }
  public void actionPerformed(ActionEvent e)
  {

 if (e.getSource()==button)
 { int month=1;
   month=Integer.parseInt(text1.getText());
   while (month<1||month>12)
   { text1.setText("");
     text1.setEditable(true);
     text2.setText("输入错误，请输入1……12之间的数");
     
     month=Integer.parseInt(text1.getText().trim());
   }

  switch (month){
    case 1: text2.setText("January 31days");break;
    case 2: text2.setText("February 28days");break;
    case 3: text2.setText("March 31days");break;
    case 4: text2.setText("April 30days");break;
    case 5: text2.setText("May 31days");break;
    case 6: text2.setText("June 30days");break;
    case 7: text2.setText("July 31days");break;
    case 8: text2.setText("August 31days");break;
    case 9: text2.setText("September 30days");break;
    case 10: text2.setText("October 31days");break;
    case 11: text2.setText("November 30days");break;
    case 12: text2.setText("December 31days");break;
  }}
  }
}