关于GridBagLayout

麻烦有人看下我的程序，为什么3个JLIST的窗口跑到右边去了，我的想法是想让他们在JTextField下面的import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;public class GridBagWindow extends JFrame {
 private JTextArea text;
    private JButton okButton,cancelButton;
    private JList fontName,fontSize,fontStyle;
    private JTextField copy1,copy2,copy3;
    GraphicsEnvironment g;//定义系统字体对象
    String[]    size = {"8","10","12","14","16","18","20","22","24","26","28","32","36","48","72","96"};
    String[]    style= {"PLAIN","BOLD","ITALIC"};
 public GridBagWindow() {
   Container font = getContentPane();
   JLabel label1=new JLabel("Font:");
   JLabel label2=new JLabel("Style:");
   JLabel label3=new JLabel("Size:");
   g = GraphicsEnvironment.getLocalGraphicsEnvironment();//获取系统字体
   String[] fontname = g.getAvailableFontFamilyNames();
   fontName = new JList(fontname);
   fontName.setVisibleRowCount(5);
   fontName.setFixedCellWidth(170);
   copy1= new JTextField(1);
   copy1.setColumns(17);
   fontName.addListSelectionListener(new Handler());
   
   fontStyle = new JList(style);
   fontStyle.setVisibleRowCount(5);
   fontStyle.setFixedCellWidth(80);
   copy2= new JTextField(1);
   copy2.setColumns(10);
   fontStyle.addListSelectionListener(new Handler());
   
   fontSize = new JList(size);
   fontSize.setVisibleRowCount(5);
   fontSize.setFixedCellWidth(80);
   copy3= new JTextField(1);
   copy3.setColumns(10);
   fontSize.addListSelectionListener(new Handler());
   
   okButton = new JButton("OK");
   cancelButton = new JButton("Cancel");
   
   GridBagLayout layout = new GridBagLayout();
   font.setLayout(layout);
   GridBagConstraints n = new GridBagConstraints();
   n.fill =GridBagConstraints.VERTICAL;
   n.gridx = 0;
   n.gridy = 0;
   layout.setConstraints(label1,n);
   font.add(label1);
   
   n.gridx = 2;
   n.gridy = 0;
   layout.setConstraints(label2,n);
   font.add(label2);
   
   n.gridx = 3;
   n.gridy = 0;
   layout.setConstraints(label3,n);
   font.add(label3);
   
   n.gridx = 0;
   n.gridy = 1;
   n.gridwidth = 2;
   layout.setConstraints(copy1,n);
   font.add(copy1);
   
   n.gridx = 2;
   n.gridy = 1;
   n.gridwidth = 1;
   layout.setConstraints(copy2,n);
   font.add(copy2);
   
   n.gridx = 3;
   n.gridy = 1;
   n.gridwidth = 1;
   layout.setConstraints(copy3,n);
   font.add(copy3);
   
   n.gridx = 4;
   n.gridy = 1;
   layout.setConstraints(okButton,n);
   font.add(okButton);
   
   n.gridx = 0;
   n.gridy = 2;
   n.gridwidth = 2;
   layout.setConstraints(fontName,n);
   font.add(new JScrollPane(fontName));
   
   n.gridx = 2;
   n.gridy = 2;
   layout.setConstraints(fontStyle,n);
   font.add(new JScrollPane(fontStyle));
   
   n.gridx = 3;
   n.gridy = 2;
   layout.setConstraints(fontSize,n);
   font.add(new JScrollPane(fontSize));
   
   n.gridx = 4;
   n.gridy = 2;
   layout.setConstraints(cancelButton,n);
   font.add(cancelButton);
   
  addWindowListener(new WindowAdapter() {
    public void windowClosing(WindowEvent e) {
     System.exit(0);
    }
  });
}
 public static void main(String args[]) {
  GridBagWindow window = new GridBagWindow();
  window.setTitle("GridBagWindow");
  window.pack();
  window.setVisible(true);
 }
 private class Handler implements ListSelectionListener
 {
  public void valueChanged(ListSelectionEvent event)
{
  copy1.setText((String)fontName.getSelectedValue());
copy2.setText((String)fontStyle.getSelectedValue());
copy3.setText((String)fontSize.getSelectedValue());
}
 }
}