Java和MySQL做一个mini版学生管理系统

主界面：

/*
 * mini 版学生管理系统
 * 1. 查询
 * 2. 添加
 * 3. 删除
 * 4. 修改
 */
package model2;

import java.awt.event.*;
import java.sql.Connection;
import java.sql.PreparedStatement;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;

public class StuManage extends JFrame implements ActionListener{

	JPanel jp1, jp2;
	JLabel jl1;
	JButton jb1, jb2, jb3, jb4;
	JTable jt = null;
	JScrollPane jsp = null;
	JTextField jtf;
	JTable jt2 = null;
	JScrollPane jsp2 = null;
	
	Connection conn = null;
	PreparedStatement ps = null;
	
	StuModel stu;
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		StuManage demo = new StuManage();
	}

	public StuManage(){
		jp1 = new JPanel();
		jtf = new JTextField(10);
		jb1 = new JButton("查询");
		jb1.addActionListener(this);
		jl1 = new JLabel("请输入名字");
		
		jp1.add(jl1);
		jp1.add(jtf);
		jp1.add(jb1);
		
		jp2 = new JPanel();
		jb2 = new JButton("添加");
		jb2.addActionListener(this);
		jb3 = new JButton("修改");
		jb3.addActionListener(this);
		jb4 = new JButton("删除");
		jb4.addActionListener(this);
		
		jp2.add(jb2);
		jp2.add(jb3);
		jp2.add(jb4);
		
		StuModel stu = new StuModel();
		String[] paras = {"1"};
		stu.queryStu("select * from stu where 1=?", paras);
		
		jt = new JTable(stu);
		
		jsp = new JScrollPane(jt);
		
		this.add(jsp);
		this.add(jp1, "North");
		this.add(jp2, "South");
		
		this.setSize(400, 300);
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		this.setVisible(true);
	}

	@Override
	public void actionPerformed(ActionEvent e) {
		
		if(e.getSource() == jb1){
			String name = this.jtf.getText().trim();
			
			String sql = "select * from stu where stuName=?";
			String[] paras = {name};
			
			stu = new StuModel();
			stu.queryStu(sql, paras);
			
			jt.setModel(stu);
		}else if(e.getSource() == jb2){
			
			StuAddDialog sa = new StuAddDialog(this, "添加", true);
			
			stu = new StuModel();
			String[] paras = {"1"};
			stu.queryStu("select * from stu where 1=?", paras);
			jt.setModel(stu);
			
		}else if(e.getSource() == jb3){
			int rowNum = this.