Java 操作MySql Blob字段

import java.sql.*;

import java.io.*;

import javax.swing.*;

import java.awt.*;

import java.awt.event.*;

class myImg

{

       Connection conn;

       Statement st;

       PreparedStatement ps,pu;

       ResultSet rs;

       JLabel l1;

       JFrame f;

       JFileChooser jf;

       String fn;

       JTextField t1,t2;

       JButton bi,bimg,bf,bp,bn,bl;

       JPanel p1,p2,p3,p4;

       myImg()

       {    

              f=new JFrame("图片字段操作");

              f.setDefaultCloseOperation(3);

              f.setBounds(100,100,600,500);

              jf=new JFileChooser(".");

              Container c=f.getContentPane();

              c.setLayout(new BorderLayout());

              p1=new JPanel();

              p2=new JPanel();

              p3=new JPanel();

              p4=new JPanel();

              p4.setLayout(new BorderLayout());

              bi=new JButton("插入记录");

              bf=new JButton("第一条记录");

              bp=new JButton("上一条记录");

              bn=new JButton("下一条记录");

              bl=new JButton("最后条记录");

              bimg=new JButton("修改照片");

              t1=new JTextField(10);

              t2=new JTextField(10);

              p3.add(t1);

              p3.add(bi);

              p3.add(bimg);

              p2.add(t2);p2.add(p3);p2.add(bf);p2.add(bp);p2.add(bn);p2.add(bl);

              p4.add(p2,"Center");

              p4.add(p3,"South");

              l1=new JLabel("");

              p1.add(l1);

              c.add(p1,"North");

              c.add(p4,"South");

              f.setVisible(true);

              try

              {

                     Class.forName("com.mysql.jdbc.Driver");

                     conn=DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/myschool","root","root");

                     ps=conn.prepareStatement("insert into img values(null,?,?)");

                     pu=conn.prepareStatement("Update img  set Img=? where SName=?");

                     st=conn.createStatement();

                     rs=st.executeQuery("select * from img");

                     rs.next();

                     mm();

              }

              catch(ClassNotFoundException ex){}

              catch(SQLException exx){}

             

              bf.addActionListener(new ActionListener()

              {

                     public void actionPerformed(ActionEvent e)

                     {

                            try

                            {

                                   rs.first();

                                   mm();

                            }

                            catch(SQLException ex){}

                     }

              });

              bp.addActionListener(new ActionListener()

              {

                     public void actionPerformed(ActionEvent e)

                     {

                            try

                            {

                                   rs.previous();

                                   mm();

                            }

                            catch(SQLException ex){}

                     }

              });

              bn.addActionListener(new ActionListener()

              {

                     public void actionPerformed(ActionEvent e)

                     {

                            try

                            {

                                   rs.next();

                                   mm();

                            }

                            catch(SQLException ex){}

                     }

              });

              bl.addActionListener(new ActionListener()

              {

                     public void actionPerformed(ActionEvent e)

                     {

                            try

                            {

                                   rs.last();

                                   mm();

                            }

                            catch(SQLException ex)

                            {

                                   System.out.println("error");

                            }

                     }

              });

              bi.addActionListener(new ActionListener()

              {

                     public void actionPerformed(ActionEvent e)

                     {

                            InputStream in=null;

                            if(jf.showDialog(f,"插入图片")==JFileChooser.APPROVE_OPTION);

                            {

                                   fn=jf.getSelectedFile().getPath();

                                   try

                                   {

                                          File f=new File(fn);

                                          in=new FileInputStream(f);

                                          ps.setString(2,t1.getText().trim());

                                          ps.setBinaryStream(1,in,(int)f.length());

                                          pu.executeUpdate();

                                          rs=st.executeQuery("select * from img");

                                   }

                                   catch(SQLException exx)

                                   {

                                          System.out.println("error1");

                                   }

                                   catch(IOException ex)         

                                   {

                                          System.out.println("error2");

                                   }

                            }                         

                     }

              });

              bimg.addActionListener(new ActionListener()

              {

                     public void actionPerformed(ActionEvent e)

                     {

                            InputStream in=null;

                            if(jf.showDialog(f,"插入图片")==JFileChooser.APPROVE_OPTION);

                            {

                                   fn=jf.getSelectedFile().getPath();

                                   try

                                   {

                                          File f=new File(fn);

                                          in=new FileInputStream(f);

                                          pu.setBinaryStream(1,in,(int)f.length());

                                          pu.setString(2,t2.getText().trim());

                                          pu.executeUpdate();

                                          rs=st.executeQuery("select * from img");

                                   }

                                   catch(SQLException exx)

                                   {

                                          System.out.println("error1");

                                   }

                                   catch(IOException ex)

                                   {

                                          System.out.println("error2");

                                   }

                            }                         

                     }

              });

       }

       void mm()  throws SQLException

       {    

              t2.setText(rs.getString(2));

              Blob blob=rs.getBlob(3);

              if(blob!=null)

              {

                     ImageIcon icon=new ImageIcon(blob.getBytes(1L,(int)blob.length()));

                     l1.setIcon(icon);

              }

              else

                     l1.setIcon(null);

       }

       public static void main(String[] ss)

       {

              new myImg();

       }

}