将图片转换成二进制，然后再显示图片！

package com.jh.loginwindow;

import java.awt.Graphics;
import java.awt.Image;
import java.awt.Label;
import java.awt.MediaTracker;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import java.io.*;

import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;

class TryBufferout extends JFrame{
public static byte[] imageToBytes(Image image, String format) {
BufferedImage bImage = new BufferedImage(image.getWidth(null),
image.getHeight(null), BufferedImage.TYPE_INT_ARGB);
Graphics bg = bImage.getGraphics();
bg.drawImage(image, 0, 0, null);
bg.dispose();
ByteArrayOutputStream out = new ByteArrayOutputStream();
try {
ImageIO.write(bImage, format, out);
} catch (IOException e) {
}
return out.toByteArray();
}
public static void main(String[] args) {
ImageIcon icon = new ImageIcon("D:\\QQ.png");
Image image = icon.getImage();
byte[] b=imageToBytes(image,"png");
Image imagee=bytesToImage(b);
TryBufferout t= new TryBufferout();
t.setSize(400,400);
ImageIcon imag=new ImageIcon();
imag.setImage(imagee);
System.out.println(imag);
t.add(new JLabel(imag));
t.setVisible(true);
}

public static Image bytesToImage(byte[] bytes) {
Image image = Toolkit.getDefaultToolkit().createImage(bytes);
try {
MediaTracker mt = new MediaTracker(new Label());
mt.addImage(image, 0);
mt.waitForAll();
} catch (InterruptedException e) {
}
return image;
}

}



下面也是经过自己的实践所写的代码
package com.jh.loginwindow;

import java.awt.Image;
import java.awt.Label;
import java.awt.MediaTracker;
import java.awt.Toolkit;
import java.io.*;
import java.sql.*;

import javax.swing.ImageIcon;

public class PutImg extends SuperDao {
Statement stmt;
PreparedStatement pstmt = null;
public void putimg() {
String sql = "";
File file = new File("d:\\world.gif");
InputStream photoStream;
try {
photoStream = new FileInputStream(file);
    sql = "INSERT INTO testpictrue  (image) VALUES (?)";
pstmt = getConnection().prepareStatement(sql);
pstmt.setBinaryStream(1, photoStream, (int) file.length());
pstmt.executeUpdate();
pstmt.close();
} catch (Exception e) {
e.printStackTrace();
}
}
public Image blobRead() throws Exception {
  FileOutputStream fos = null;
  InputStream is = null;
  byte[] Buffer = new byte[4096];
  try {
       pstmt = getConnection().prepareStatement("select image from testpictrue where id=?");
       pstmt.setInt(1, 1); // 传入要取的图片的ID
  ResultSet rs = pstmt.executeQuery();
  rs.next();
is = rs.getBinaryStream("image");
  byte[] b = new byte[is.available()];//声明
  is.read(Buffer);//将二进制输入流读入字节数组
  Image image= bytesToImage(Buffer);  
return image;
  } catch (Exception e) {
  return null;
  } finally {
   // 关闭用到的资源

  }
}
   public  Image bytesToImage(byte[] bytes) {
Image image = Toolkit.getDefaultToolkit().createImage(bytes);
try {
MediaTracker mt = new MediaTracker(new Label());
mt.addImage(image, 0);
mt.waitForAll();
} catch (InterruptedException e) {
}
return image;
}

public static void main(String args[]) {
PutImg pi = new PutImg();
try {
Image image=pi.blobRead();
new TryBufferout(image);//在这个界面上显示
} catch (Exception e) {

e.printStackTrace();
}
}
}