java中文件浏览对话框中怎么过滤文件类型

代码如下:
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.sql.Date;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.border.EmptyBorder;
import javax.swing.event.CaretEvent;
import javax.swing.event.CaretListener;
import javax.swing.table.DefaultTableModel;

public class ListCustomTypeFile extends JFrame {
/**
*
*/
private static final long serialVersionUID = -6263975104443132420L;

/**
* 自定义扩展名过滤器
*