Java第五次作业

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.io.File;
import java.util.ArrayList;
import java.util.List;

import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;


public class FileUtil extends JFrame{

	/**
	 * @param args
	 */
	
	public static String listDirectory(File dir) throws IllegalAccessException{
		if(!dir.exists()){
			throw new IllegalAccessException("目录"+dir+"不存在");
		}
		if(!dir.isDirectory()){//判断是不是目录
			throw new IllegalArgumentException(dir+"不是目录");
		}
		String[] fileName = dir.list();    
		String name ="";
		for(String a : fileName){
			name=name+a+"\n";}
		return name;
		}
	
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		JFrame frame=new JFrame();
		JPanel main_panel =new JPanel(new BorderLayout());
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		//frame.setLayout(null);
		String[] itme =new String[]{"all",".wav",".au"};
		JComboBox box=new JComboBox();
		for(int i=0;i<itme.length;i++){
			box.addItem(itme[i]);
		}
		box.setEnabled(true);
		box.setEditable(true);
		box.setMaximumRowCount(6);
		box.setBounds(230,30,130,25);
	
		
		frame.setBounds(400,300,400,200);
		frame.setVisible(true);
		JTextArea main_text =new JTextArea();
		 main_text.setBackground(Color.BLACK);
		JScrollPane AA=new JScrollPane();
		AA.setViewportView(main_text);
		main_text.setEnabled(false);
		main_panel.add(box,BorderLayout.NORTH);
		main_panel.add(AA,BorderLayout.CENTER);
		frame.add(main_panel);
		
		try {
			String str=FileUtil.listDirectory(new File("C:\\Users\\Administrator\\Desktop\\Java作业5\\soundPlayer\\audio"));
			main_text.setText(str);
		}
		catch (IllegalAccessException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		

		
		frame.setBounds(400,200,400,200);
		frame.setVisible(true);
		
	
		
		

	
	}
}