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 FileUtils 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+"
";}
    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=FileUtils.listDirectory(new File("C:\Users\lenovo\Desktop\Java作业5\soundPlayer"));
        main_text.setText(str);
    }
    catch (IllegalAccessException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }      frame.setBounds(400,200,400,200);
    frame.setVisible(true);
}

}