java圖形gui界面的創建

package jdbc;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.sql.*;
import java.util.*;


public class reguser extends JFrame {
	//定義窗體變量
	private JButton reg;
	private JButton show;
	private JButton edit;
	private JButton del;
	private JPanel up;
	private JPanel down;
	private JLabel uptext;
	private JTextField user;
	private JTextField pass;
	private JLabel result;
	private JButton regsave=new JButton("提交注冊");
	private JButton editpass=new JButton("修改密碼");
	private Mapusermap=new HashMap();
	//定義數據庫變量
	Statement stmt = null;
	Connection conn = null;
	ResultSet rs = null;

JFrame f=new JFrame("注冊窗口");
		f.setSize(300,200);
		f.setLocation(300,200);
		reg=new JButton("注冊") ;
		show=new JButton("查看");
		edit=new JButton("修改") ;
		del=new JButton("刪除");
		f.setLayout(new BorderLayout());
		up=new JPanel() ;
		
		f.add(up,BorderLayout.NORTH);
		f.add(down,BorderLayout.SOUTH);
		down.add(reg);
		down.add(show);
		down.add(edit);
		down.add(del);
		uptext=new JLabel("用戶注冊界面");
		uptext.setFont(new Font("宋體",Font.PLAIN,30));
		up.add(uptext);
		f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		
		
		//菜單
		JMenuBar menuBar = new JMenuBar(); 
		JMenu menu = new JMenu("操作");
		JMenuItem item1 = new JMenuItem("注冊用戶");
		JMenuItem item2 = new JMenuItem("關閉");
		f.setJMenuBar(menuBar);
		menuBar.add(menu);
		menu.add(item1);
		menu.add(item2);
		f.setVisible(true);
		
		//按鈕注冊彈窗
		reg.addActionListener(new ActionListener() { 
			public void actionPerformed(ActionEvent e) {
				reg();	
			}
		});