Java链接SqlServer，学生数据管理面板

package pkg;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.*;
import javax.swing.*;
public class 第三题 {
	static Connection con;
	JButton jb1,jb2,jb3;
	JTextField jtf1,jtf2,jtf3,jtf4;
	JRadioButton nan,nv;
	public Connection getConnection() {
		try {
			Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
			System.out.println("数据库驱动加载成功");
		}catch(ClassNotFoundException e) {
			e.printStackTrace();
		}
		try {
			con = DriverManager.getConnection("jdbc:sqlserver:"
					+ "//127.0.0.1:1433;DatabaseName=aaa","sa","123456");
			System.out.println("数据库连接成功");
			
		}catch(SQLException e) {
			e.printStackTrace();
		}
		return con;
	}
	第三题() {		
		JFrame jf = new JFrame("学生信息录入系统");
		JPanel jp = new JPanel(); 
		jp.setBackground(Color.LIGHT_GRAY);
		String[] jlName = {"学号","姓名","性别","出生日期","籍贯"};
		Box box = Box.createHorizontalBox();
		Box box1 = Box.createVerticalBox();
		Box box2 = Box.createVerticalBox();
		Box box3 = Box.createHorizontalBox();
		Box box4 = Box.createHorizontalBox();
		for(int i = 0;i<jlName.length;i++) {
			JLabel jl = new JLabel(jlName[i]); 
			box1.add(Box.createVerticalStrut(12));
			box1.add(jl);
		}
		box1.add(Box.createHorizontalStrut(40));
		nan = new JRadioButton("男");
		nan.setBackground(Color.cyan);
		nv = new JRadioButton("女");
		nv.setBackground(Color.PINK);
		ButtonGroup bg = new ButtonGroup();
		box3.add(nan);box3.add(Box.createHorizontalStrut(30));
		box3.add(nv);
		bg.add(nan);bg.add(nv);
		JLabel jl1 = new JLabel("注意：出生日期输入格式为YYYY/MM/DD");
		jtf1 = new JTextField(10);
		jtf2 = new JTextField(10);
		jtf3 = new JTextField(10);
	    jtf4 = new JTextField(12);
		box2.add(Box.createHorizontalStrut(20));
		box2.add(Box.createVerticalStrut(10));
		box2.add(jtf1); box2.add(Box.createVerticalStrut(8)); 
		box2.add(jtf2); box2.add(Box.createVerticalStrut(5));
		box2.add(box3); 
		box2.add(jtf3);  box2.add(jl1);
		box2.add(jtf4);
		jb1 = new JButton("存入");
		jb2 = new JButton("查询");
		jb3 = new JButton("删除此id");
		box4.add(jb1);box4.add(jb2);box4.add(jb3);
		jb1.addActionListener(new jbListener1());
		jb2.addActionListener(new jbListener2());
		jb3.addActionListener(new jbListener3());
		box2.add(box4);
		box.add(box1);
		box.add(Box.createHorizontalStrut(20));
		box.add(box2);
		jp.add(box);
		jf.add(jp);
		jf.setBounds(300, 300, 500, 300);
		jf.setVisible(true);
    }
	
	class jbListener1 implements ActionListener{
		String data1,data2,data3,data4,data5;
        String sql;Statement stmt;
		public void actionPerformed(ActionEvent e) {
			data1 = jtf1.getText();
			data2 = jtf2.getText();
			if(nan.isSelected()) {
				data3 = "男";
			}else {
				data3 = "女";
			}
			data4 = jtf3.getText();
			data5 = jtf4.getText();
	        try {	
	    		String sql = "insert into stu values(?,?,?,?,?)";
	    		PreparedStatement pstmt = con.prepareStatement(sql);
	    		pstmt.setString(1, data1);
	    		pstmt.setString(2, data2);
	    		pstmt.setString(3, data3);
	    		pstmt.setString(4, data4);
	    		pstmt.setString(5, data5);	
	    		pstmt.executeUpdate();
	    		System.out.println("添加完毕");
	        }catch(Exception e1) {
	        	e1.printStackTrace();
	        }
		}
	}
	class jbListener2 implements ActionListener{
        String sql;Statement stmt;
		public void actionPerformed(ActionEvent e) {
	        try {	
	    		sql = "select*from stu";
    			stmt = con.createStatement();//sql语句对象
	    		ResultSet res = stmt.executeQuery(sql);
	    		while(res.next()) {
	    			String id = res.getString("id");
	    			String name = res.getString("name");
	    			String sex = res.getString("sex");
	    			String birthday = res.getString("birthday");
	    			String place = res.getString("place");
	    			System.out.println("编号:"+id+"姓名:"+name+"性别:"+sex+"生日:"+birthday+"地址："+place+'\n');
	    		}
	    		System.out.println("查询完毕");
	        }catch(Exception e1) {
	        	e1.printStackTrace();
	        }
		}
	}
	class jbListener3 implements ActionListener{
        String sql;PreparedStatement ps;
		public void actionPerformed(ActionEvent e) {
	        try {	
	        	String ID;
	        	ID = jtf1.getText();
	        	sql ="delete from stu where id=?";
	        	ps = con.prepareStatement(sql);
	        	ps.setString(1, ID);
	        	ps.executeUpdate();
	    		System.out.println("删除完毕");
	        }catch(Exception e1) {
	        	e1.printStackTrace();
	        }
		}
	}
	public static void main(String[]args) {
		第三题 c = new 第三题();		
		c.getConnection();			
	}
}