import java.util.*;import java.applet.*;import java.awt.*;
import javax.swing.*;import java.awt.event.*;
public class J509 extends Applet implements ActionListener{
  JTextArea textA;JTextField textF;JButton b1,b2;
  public void init(){
    setSize(250,150);
    textA=new JTextArea("",5,10);
    textA.setBackground(Color.cyan);
    textF=new JTextField("",10);
    textF.setBackground(Color.pink);
    b1=new JButton("求 和"); b2=new JButton("重新开始");
    textF.setEditable(false);
    b1.addActionListener(this); b2.addActionListener(this);
    add(textA); add(textF); add(b1);add(b2);
  }
  public void actionPerformed(ActionEvent e){
    if(e.getSource()==b1){
      String s=textA.getText();
      StringTokenizer tokens=new StringTokenizer(s);
      //使用默认的分隔符集合：空格、换行、Tab符合回车作分隔符
      int n=tokens.countTokens(),sum=0,i;
      for(i=0;i<=n-1;i++){
        String temp=tokens.nextToken();//从文本区取下一个数据
        sum+=Integer.parseInt(temp);
      } 
      textF.setText(""+sum);
    }
    else if(e.getSource()==b2){
      textA.setText(null);
      textF.setText(null);
    }
  }
}

import java.applet.*;import javax.swing.*;
import java.awt.*;import java.awt.event.*;
class Panel1 extends JPanel{
  JTextField text1,text2,text3;
  Panel1(){//构造方法。当创建Panel对象时，Panel被初始化为有三个标签
    //三个文本框，布局为GridLayout(1,6)
    text1=new JTextField(10);text2=new JTextField(10);
    text3=new JTextField(10);setLayout(new GridLayout(1,6));
    add(new JLabel("起始数",JLabel.RIGHT));add(text1);
    add(new JLabel("终止数",JLabel.RIGHT));add(text2);
    add(new JLabel("因子",JLabel.RIGHT));add(text3);
  }
}
class Panel2 extends JPanel{//扩展Panel类
  JTextArea text;JButton Button;
  Panel2(){//构造方法。当创建Panel对象时，Panel被初始化为有一个标签
    //一个文本框，布局为GridLayout(1,4)
    text=new JTextArea(4,10);text.setLineWrap(true);
    JScrollPane jsp=new JScrollPane(text);
    Button=new JButton("开始计算");
    setLayout(new GridLayout(1,4));
    add(new JLabel("计算结果：",JLabel.RIGHT));
    add(jsp);
    add(new Label());add(Button);
  }
}
public class J510 extends Applet implements ActionListener{
  Panel1 panel1;Panel2 panel2;
  public void init(){
    setLayout(new GridLayout(3,1));
    setSize(400,200);panel1=new Panel1();panel2=new Panel2();
    add(new JLabel("计算从起始数到终止数是因子倍数的数",JLabel.CENTER));
    add(panel1);add(panel2);
    (panel2.Button).addActionListener(this);
  }
  public void actionPerformed(ActionEvent e){
    if(e.getSource()==(panel2.Button)){
      long n1,n2,f,count=0;
      n1=Long.parseLong(panel1.text1.getText());
      n2=Long.parseLong(panel1.text2.getText());
      f=Long.parseLong(panel1.text3.getText());
      for(long i=n1;i<=n2;i++){
        if(i%f==0)
        panel2.text.append(String.valueOf(i)+"");
      }
    }
  }
}