请问如何向下面的表设置表头
import javax.swing.*;
import java.awt.event.*;
public class Table extends JFrame{
public Table(){
super("表格");
setSize(500,500);
setLocation(100,100);
final JTable jtable = new JTable(4,4);
JButton jb = new JButton("输出");
jb.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent ae){
String str =(String)jtable.getValueAt(1, 1);
System.out.println(str);
}
});
add(jb,"North");
add(jtable,"Center");
setVisible(true);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public static void main(String[]args){
new Table();
}
}