使用Java对数据库进行基本的查询和更新操作

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import java.sql.*;
public class Example10_9 extends JFrame implements ActionListener{
  public static Connection connectByJdbcodbc(String url, String username,String password){
    Connection con = null;
    try{
      Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); //加载ODBC驱动程序
    }
    catch (Exception e){
      e.printStackTrace();
      return null; //加载失败，连接不成功
    }
    try{
      con = DriverManager.getConnection(url, username, password);
    }
    catch (SQLException e){
      e.printStackTrace();
      return null; //连接失败
    }
    return con; //连接成功
  }
  String title[] ={"考号", "姓名", "成绩", "地址", "简历"};
  JTextField txtNo = new JTextField(8);
  JTextField txtName = new JTextField(10);
  JTextField txtScore = new JTextField(3);
  JTextField txtAddr = new JTextField(30);
  JTextArea txtresume = new JTextArea();
  JButton prev = new JButton("前一个");
  JButton next = new JButton("后一个");
  JButton first = new JButton("第一个");
  JButton last = new JButton("最后一个");
  Statement sql; //SQL语句对象
  ResultSet rs; //存放查询结果对象
  Example10_9(Connection connect){
    super("考生信息查看窗口");
    setSize(450, 350);
    try{
      sql = connect.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
      rs = sql.executeQuery("SELECT * FROM ksInfo");
      Container con = getContentPane();
      con.setLayout(new BorderLayout(0, 6); JPanel p[] = new JPanel[4];
      for (int i = 0; i < 4; i++){
        p[i] = new JPane(new FlowLayout(FlowLayout.LEFT, 8, 0));
        p[i].add(new JLabel(title[i]));
      }
      p[0].add(txtNo);
      p[1].add(txtName);
      p[2].add(txtScore);
      p[3].add(txtAddr);
      JPanel p1 = new JPane(new GridLayout94, 1, 0, 8));
      JScrollPane jsp = new JScrollPane(txtResume,
        JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
        JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
        jsp.setPreforredSize(new Dimension(300, 60);
      for (int i = 0; i < 4; i++){
        p1.add(p[i]);
      }
      JPanel p2 = new JPanel(new FlowLayout(FlowLayout.LEFT, 10, 0);
      p2.add(new JLabel(title[4]));
      p2.add(jsp);
      Jpanel p3 = new Jpanel();
      p3.add(prev);
      p3.add(next);
      p3.add(first);
      p3.add(last);
      prev.addActionListener(this);
      next.addActionListener(this);
      first.addActionListener(this);
      last.addActionlistener(this);
      rs.first();
      readRecord();
    }
    catch (Exception e){
      e.printStackTrace():
    }
    setVisible(ture);
  }
  public void modifyRecord(Connection connect){
    String stuNo = (String)JOptionPane.showInputDialog(null,
      "请输入考生考号", "输入考号对话框", JOptionPane.PLAIN_MESSAGE, null,
      null, "");
    try {
      sql = connect.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
      rs = sql.executeQuery("SELECT * FROM ksInfo");
      Container con = getContentPane();
      con.setLayout(new Boarderlayout(0, 6));
      Jpanel p[] = new JPanel[4];
      for (int i = 0; i < ; i++){
        p[i] = new JPane(new FlowLayout(flowLayout.LEFT, 8, 0));
        p[i].add(new JLabel(title[i]));
      }
      p[0].add(txtNo);
      p[1].add(txtName);
      p[2].add(txtScore);
      p[3].add(txtAddr);
      Jpanel p1 = new Jpane(new GridLayout(4, 1, 0, 8));
      JScrollPane jsp = new JScrollPane(txtResume,
        JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
        JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
      jsp.setPreferredSize (new dimension(300, 60));
      for (int i = 0; i < 4; i++){
        p1.add(p[i]);
      }
      Jpanel p2 = new JPanel(new FlowLayout(FlowLayout.LEFT, 10, 0));
      p2.add(new JLableI(title[4]));
      p2.add(jsp);
      JPanel p3 = new JPanel();
      p3.add(prev);
      p3.add(next);
      p3.add(first);
      p3.add(last);
      prev.addActionListener(this);
      next.addActionListener(this);
      first.addActionListenerIthis);
      last.addActionListener(this);
      rs.first();
      readRecord();
    }
    catch (Exception e){
      e.printStackTrace();
    }
    setVisible(true);
  }
  boolean readRecord(){
    try{
      txtNo.setText(rs.getString("考号")); txtName.setText(rs.getString("姓名")); txtScore.setText(rs.getString("成绩"));
      txtAddr.setText(rs.getString("地址")); txtResume.setText(rs.getString("简历"));
    }
    catch (SQLException e){
      e.printStackTrace(); return false;
    }
    return true;
  }
  public void actionPerformed(ActionEvent e){
    try{
      if (e.getSource() == prev)rs.previous();
      else if (e.getSource() == next)rs.next();
      else if (e.getSource() == first)rs.first();
      else if (e.getSource() == last)rs.last(); readRecord();
    }
    catch (Exception e2){}
  }
  public static void main(String args[]){
    connection connect = null;
    JFrame .setDefaultLookAndFeeDecorated(true);
    Font font = new Font("JFrame", Font.PLAIN, 14);
    if ((connect =connectByJdbcOdbc("jdbc:odbc:redsun", "xia", "1234")) == null){
      JOptionPane.showMessageDialog(null, "数据库连接失败!");
      System.exit ( - 1);
    }
    new Example10_9(connect); //创建对象
  }
}

  stmt = connect.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_UPDATABLE);