Java数据库系统项目开发实践2这本书的所有代码

				package sfms;								import java.awt.*;				import javax.swing.*;				import java.sql.*;				import java.awt.event.*;								public class delete extends JFrame implements ActionListener{				   JButton yesB,cancelB;				   JTextField text1;				   String SNO;								  public delete(){				    Container c=this.getContentPane();				    c.setLayout(new GridLayout(3,1));				    c.setFont(new Font("true",Font.TRUETYPE_FONT,13));								    JPanel p1=new JPanel();				    JPanel p2=new JPanel();								    //first,add the label				    JLabel label1=new JLabel("删除学生档案",SwingConstants.CENTER);				    label1.setFont(new Font("TRUE",Font.TRUETYPE_FONT,20));				    label1.setForeground(Color.blue);				    c.add(label1);								    //set the input dialog frame				    JLabel label2=new JLabel("请输入学生号");				    text1=new JTextField(10);				    p1.add(label2);				    p1.add(text1);				    c.add(p1);								    //set the buttons				     yesB=new JButton("确定");				     cancelB=new JButton("退出");				    p2.add(yesB);				    p2.add(cancelB);				    c.add(p2);								    //register frames as listener for button events				    yesB.addActionListener(this);				    cancelB.addActionListener(this);				    this.setSize(400,300);				    this.setTitle("删除学生档案");				    this.setVisible(true);								    //create anonymous inner class to handle window closing event				    this.addWindowListener(new WindowAdapter()				    {				      public void windowClosing( WindowEvent event)				      {shutDown();}				    }				    );				      }				      //action performed when a Button is invoked				   public void actionPerformed(ActionEvent e){				     if(e.getSource()==yesB){				       del();				     }				     if(e.getSource()==cancelB){				       shutDown();				     }				   }								   private void del(){				    SNO=text1.getText();				    try{				      Class.forName("oracle.jdbc.OracleDriver").newInstance();				      String url="jdbc:oracle:thin:@localhost:1521:SFMS";				      Connection conn=DriverManager.getConnection(url,"df","1234");				      String sql="DELETE FROM DF.FILEINFO WHERE STNO='"+ SNO +"'";				      PreparedStatement ps=conn.prepareStatement(sql);				      ps.executeUpdate(sql);				      conn.close();				      JOptionPane.showMessageDialog(this,"删除成功!");				    }				    catch(SQLException e){				      System.out.println("Error Code: "+ e.getErrorCode());				      System.out.println("Message="+e.getMessage());				 }				    catch(Exception e){				  e.printStackTrace();				}								   }				   private void shutDown(){				     System.exit(0);				   }				public static void main(String args[]){				     delete dd=new delete();				   }				}