10+

本压缩文档为《Java大学实用教程》（7-121-00959-5 电子工业出版社 2005.3） 的电子教案。

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
import java.io.*;
import java.util.regex.*;
import java.util.*;
class GoodWindow extends JFrame implements ItemListener 
{  
    JComboBox list;
    JTextArea text1,text2;
    Pattern  p;        
    Matcher  m;   
    GoodWindow(String s) 
    {  
      super(s);        
      setSize(500,370);
      setLocation(120,120);
      setVisible(true);
      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      text1=new JTextArea(12,12);  
      text2=new JTextArea(12,12); 
      list=new JComboBox();
      list.addItem("Example.java");
      list.addItem("A.java");
      list.addItem("B.java");
      Container con=getContentPane();
      con.setLayout(new FlowLayout());
      con.add(list);
      con.add(new JScrollPane(text1));
      con.add(new JScrollPane(text2));
      con.validate();
      validate();
      list.addItemListener(this);
     } 
   public void itemStateChanged(ItemEvent e)
    { 
        String fileName=(list.getSelectedItem()).toString();
        File readFile=new File(fileName);
        text1.setText(null);
        text2.setText(null);
       try{
           FileReader  inOne=new FileReader(readFile);
           BufferedReader inTwo= new BufferedReader(inOne);
           FileWriter  tofile=new FileWriter("hello.txt");
           BufferedWriter out= new BufferedWriter(tofile);
           String s=null;
           int i=0;
           while((s=inTwo.readLine())!=null)
           {
               text1.append("\n"+s);
           }
           out.flush();
           out.close();
           tofile.close();
           String  content=text1.getText();    //待匹配的字符序列。
           p=Pattern.compile("[\\s(]{1}[A-Z]+\\w+");//初试化模式对象:空格或'('开头的大写单词。
           m=p.matcher(content);
           TreeSet<String> tree=new TreeSet<String>();        
           while(m.find())
           {
              String str=m.group();
              str=str.substring(1);          //去掉空格或'('字符.
              tree.add(str);
           } 
           Iterator<String> iter=tree.iterator();
           while(iter.hasNext())
           {
              String item=iter.next();
              text2.append("\n"+item);
           }
         }
       catch(IOException ex)
           {
              text1.setText(ex.toString());   
           }
     }
}
public class Example
{  
    public static void main(String args[])
    { 
      GoodWindow win=new GoodWindow("窗口");
    }
}