javaswingmysql下面的代码无法连接到数据库，插入数据

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.sql.*;

class Test
{
/*private String driver="com.mysql.jdbc.Driver";
private String url="jdbc:mysql://localhost:3306/technology";
private String user="root";
private String pass="root";*/

JFrame f;Dialog d1,d2,r_interface;JButton jb1,jb2,b3,b4,b5,r_inquire,r_insert,r_delete;JLabel jl,l1,l2;TextField tf1;TextField tf2;Test(){    init();}public void init(){    /*try {        Class.forName(driver);    } catch (ClassNotFoundException e1) {        // TODO Auto-generated catch block        e1.printStackTrace();    }*/    f=new JFrame();    jl=new JLabel("江西农业大学三检工作系统");    jb1=new JButton("登陆");    jb2=new JButton("注册");    f.setVisible(true);    f.setBounds(400,200,400,300);    f.setLayout(null);    f.setResizable(false);    jb1.setBounds(110,130,70,30);    jb2.setBounds(200,130,70,30);    jl.setBounds(110,70,200,50);    f.add(jb1);    f.add(jb2);    f.add(jl);    d1=new Dialog(f,"用户登陆",true);    d2=new Dialog(f,"用户注册",true);    b3=new JButton("确定");    b4=new JButton("取消");                     //登陆界面的取消按钮    b5=new JButton("取消");                     //注册界面的取消按钮    myevent();}public void myevent(){    f.addWindowListener(new WindowAdapter()             //窗口退出事件监听    {        public void windowClosing(WindowEvent e)        {            System.exit(0);        }    });    d1.addWindowListener(new WindowAdapter()                    {        public void windowClosing(WindowEvent e)        {            d1.setVisible(false);        }    });    d2.addWindowListener(new WindowAdapter()                    {        public void windowClosing(WindowEvent e)        {            d2.setVisible(false);        }    });    b3.addActionListener(new ActionListener()    //登陆界面的确定    {        public void actionPerformed(ActionEvent e)        {            dlcg();        }    });    b4.addActionListener(new ActionListener()    {        public void actionPerformed(ActionEvent e)        {            d1.setVisible(false);        }    });    b5.addActionListener(new ActionListener()    {        public void actionPerformed(ActionEvent e)        {            d2.setVisible(false);        }    });    jb1.addActionListener(new ActionListener()    {        public void actionPerformed(ActionEvent e)        {            denglu();        }    });    jb2.addActionListener(new ActionListener()    {        public void actionPerformed(ActionEvent e)        {            zhuce();        }    });}public void dlcg(){    r_interface=new Dialog(f,"登陆成功",true);    r_inquire=new JButton("查询");    r_insert=new JButton("插入");    r_delete=new JButton("删除");    r_interface.setLayout(null);    r_interface.add(r_inquire);    r_inquire.setBounds(80,60,120,30);    r_interface.setVisible(true);    Connection conn = null;    PreparedStatement psta=null;    String z_user=String.valueOf(tf1.getText());    String z_pass=String.valueOf(tf2.getText());    try {        Class.forName("com.mysql.jdbc.Driver");        conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb","root","root");        psta = conn.prepareStatement("insert into teacher (tname,tage) values (?, ?)");        psta.setString(1,z_user);        psta.setString(2,z_pass);        psta.executeUpdate();    } catch(ClassNotFoundException e) {        e.printStackTrace();    }    catch(SQLException e) {        e.printStackTrace();    }    finally {        try {            if(conn != null) {                conn.close();            }            if(psta != null) {                psta.close();            }        } catch(SQLException e) {            e.printStackTrace();        }    }    /*String z_user=tf1.getText();    String z_pass=tf2.getText();    Connection cn = null;    PreparedStatement pst = null;    try {        String sql="insert into register (r_account,r_password) values (?, ?)";        cn = DriverManager.getConnection(url,user,pass);        pst = cn.prepareStatement(sql);        pst.setString(1,z_user);        pst.setString(2,z_pass);        pst.executeUpdate();    } catch(SQLException e) {        e.printStackTrace();    } finally {        try {            if(pst!=null) {                pst.close();            }            if(cn!=null) {                cn.close();            }        } catch(SQLException e) {            e.printStackTrace();          }    }    */}public void denglu(){    l1=new JLabel("用户名");    l2=new JLabel("密    码");    tf1=new TextField();    tf2=new TextField();    tf2.setEchoChar('*');    d1.setBounds(470,240,260,230);    d1.setLayout(null);    d1.setResizable(false);    d1.add(l1);    d1.add(l2);    d1.add(b3);    d1.add(b4);    d1.add(tf1);    d1.add(tf2);    tf1.setBounds(80,60,120,30);    tf2.setBounds(80,100,120,30);    tf1.setFont(new Font("宋体",1,20));    tf2.setFont(new Font("宋体",1,20));    b3.setBounds(50,150,70,30);    b4.setBounds(150,150,70,30);    l1.setBounds(20,60,50,30);    l2.setBounds(20,100,50,30);    d1.setVisible(true);        }public void zhuce(){    l1=new JLabel("注册名");    l2=new JLabel("密    码");    //b3=new JButton("确定");    tf1=new TextField();    tf2=new TextField();    tf2.setEchoChar('*');    d2.setBounds(470,240,260,230);    d2.setLayout(null);    d2.setResizable(false);    d2.add(l1);    d2.add(l2);    d2.add(b3);    d2.add(b5);    d2.add(tf1);    d2.add(tf2);    tf1.setBounds(80,60,120,30);    tf2.setBounds(80,100,120,30);    tf1.setFont(new Font("宋体",1,20));    tf2.setFont(new Font("宋体",1,20));    b3.setBounds(50,150,70,30);    b5.setBounds(150,150,70,30);    l1.setBounds(20,60,50,30);    l2.setBounds(20,100,50,30);    d2.setVisible(true);}public static void main(String[] args){    Connection conn = null;    PreparedStatement psta=null;    new Test(); }

}