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();

}

}