JFrame显示指定类型的文件

代码：
package unitTwelve;import javax.swing.*;import javax.swing.table.DefaultTableModel;import java.awt.*;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.io.File;import java.io.FileFilter;import java.text.SimpleDateFormat;import java.util.Date;/** * 描述:显示指定类型的文件 * 作者: ChengShanyunduo * 创建日期: 2017-07-07 * 修改记录: */public class FilesList extends JFrame{    JFrame jFrame = new JFrame();    JPanel jPanel1 = new JPanel();    JPanel jPanel2 = new JPanel();    JLabel label = new JLabel("输入文件扩展名：");    JTextField jTextField = new JTextField();    JButton button = new JButton("选择文件夹");    String[] columnNames = {"文件名","文件大小","修改时间"};    String[][]data=new String[0][3];    DefaultTableModel model = new DefaultTableModel(data,columnNames);    JTable jTable = new JTable(model);    JScrollPane scroll = new JScrollPane(jTable);    FilesList(){        jPanel1.setLayout(new GridLayout(1,3));        jPanel1.setSize(450,30);        jTextField.setSize(150,30);        jPanel1.add(label);        jPanel1.add(jTextField);        jPanel1.add(button);        //监听        button.addActionListener(new ActionListener() {            @Override            public void actionPerformed(ActionEvent e) {                do_button_actionPerformed(e);            }        });        jFrame.setLayout(new FlowLayout());        jFrame.add(jPanel1);        jFrame.add(scroll);        jFrame.setSize(500,500);        jFrame.setVisible(true);    }    protected void do_button_actionPerformed(ActionEvent e){        //获取text中内容        final String fileType = jTextField.getText();        //如果为空。弹出提醒        if (fileType.isEmpty()){            JOptionPane.showMessageDialog(this,"请输入文件类型","",JOptionPane.WARNING_MESSAGE);            return;        }        //文件选择器        JFileChooser chooser = new JFileChooser();        //只能选择文件夹        chooser.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);        //禁止选择多个文件夹        chooser.setMultiSelectionEnabled(false);        //打开文件选择器        int result = chooser.showOpenDialog(this);        if (result == JFileChooser.APPROVE_OPTION){            //获得相同类型的文件            File[] listFiles = chooser.getSelectedFile().listFiles(new FileFilter(){                @Override                public boolean accept(File pathname){                    if (pathname.getName().endsWith(fileType)){                        return true;                    }else{                        return false;                    }                }            });            DefaultTableModel model = (DefaultTableModel) jTable.getModel();            SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");            //遍历File数组            for (File file : listFiles){                String name = file.getName();                long size = file.length();                String modifyDate = format.format(new Date(file.lastModified()));                model.addRow(new String[]{name,""+size,modifyDate});            }            jTable.setModel(model);        }    }    public static void main(String[] args){        FilesList a = new FilesList();    }}

结果：