mysql blob字段存儲圖片操作示例

表結構：

create table view(
    id int unsigned NOT NULL AUTO_INCREMENT, 
    catid int,title varchar(256),
    picture MEDIUMBLOB, 
    content TEXT,PRIMARY KEY (id)
);

import java.awt.Image;
import java.io.*;
import java.nio.ByteBuffer;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.ImageIcon;
import org.bean.View;

/*
 

@author weijian.zhongwj
*/
public class ViewPointDao {
public static View getView(Integer catId) {

 View view = new View();
 try {
     String sql2 = "SELECT title, content, picture FROM view where catid=? limit 1";
     PreparedStatement stmt2 = BaseDaoFactory.getInstance().prepareStatement(sql2);
     stmt2.setInt(1, catId);
     ResultSet resultSet = stmt2.executeQuery();
     while (resultSet.next()) {
         String name = resultSet.getString(1);
         String description = resultSet.getString(2);

         ByteBuffer bb = ByteBuffer.allocate(1024 * 1024);
         byte[] buffer = new byte[1];
         InputStream is = resultSet.getBinaryStream(3);

         while (is != null && is.read(buffer) > 0) {
             bb.put(buffer);
         }
         ImageIcon icon = new ImageIcon(bb.array());
         view.setImage(icon.getImage());
         view.setTitle(name);
         view.setContent(description);
         return view;
     }
 } catch (IOException ex) {
     Logger.getLogger(ViewPointDao.class.getName()).log(Level.SEVERE, null, ex);
 } catch (SQLException ex) {
     Logger.getLogger(ViewPointDao.class.getName()).log(Level.SEVERE, null, ex);
 }
 return null;

}
public static boolean addView(View view) {

 FileInputStream fis = null;
 try {

     if (exit(view.getCatId())) {
         return update(view);
     }

     String sql = "INSERT INTO view (title, content, catid, picture) VALUES (?, ?, ?, ?)";
     PreparedStatement stmt = BaseDaoFactory.getInstance().prepareStatement(sql);
     stmt.setString(1, view.getTitle());
     stmt.setString(2, view.getContent());
     stmt.setInt(3, view.getCatId());

     if (view.getImageFile() != null) {
         File image = new File(view.getImageFile());
         fis = new FileInputStream(image);
         //image.length(),返回文件的大小
         stmt.setBinaryStream(4, fis, (int) image.length());
     } else {
         stmt.setBinaryStream(4, null, 0);
     }
     int count = stmt.executeUpdate();
     if (count > 0) {
         return true;
     } else {
         return false;
     }
 } catch (IOException ex) {
     Logger.getLogger(ViewPointDao.class.getName()).log(Level.SEVERE, null, ex);
 } catch (SQLException ex) {
     Logger.getLogger(ViewPointDao.class.getName()).log(Level.SEVERE, null, ex);
 } finally {
     try {
         if (fis != null) {
             fis.close();
         }
     } catch (IOException ex) {
     }
 }
 return false;

}
public static boolean update(View view) {

 FileInputStream fis = null;
 try {
     String sql = "update view set title= ? ,content= ? " + (view.getImageFile() != null ? (",picture= ? ") : " ") + "where catid= ? ";
     PreparedStatement stmt = BaseDaoFactory.getInstance().prepareStatement(sql);
     stmt.setString(1, view.getTitle());
     stmt.setString(2, view.getContent());

     if (view.getImageFile() != null) {
         stmt.setInt(4, view.getCatId());
         File image = new File(view.getImageFile());
         fis = new FileInputStream(image);
         //image.length(),返回文件的大小
         stmt.setBinaryStream(3, fis, (int) image.length());
     } else {
         stmt.setInt(3, view.getCatId());
     }

     int count = stmt.executeUpdate();
     if (count > 0) {
         return true;
     } else {
         return false;
     }
 } catch (IOException ex) {
     Logger.getLogger(ViewPointDao.class.getName()).log(Level.SEVERE, null, ex);
 } catch (SQLException ex) {
     Logger.getLogger(ViewPointDao.class.getName()).log(Level.SEVERE, null, ex);
 } finally {
     try {
         if (fis != null) {
             fis.close();
         }
     } catch (IOException ex) {
     }
 }
 return false;

}
public static boolean exit(Integer catId) {

 try {
     String sql2 = "SELECT title, content, picture FROM view where catid=? limit 1";
     PreparedStatement stmt2 = BaseDaoFactory.getInstance().prepareStatement(sql2);
     stmt2.setInt(1, catId);
     ResultSet resultSet = stmt2.executeQuery();
     while (resultSet.next()) {
         return true;
     }
 } catch (SQLException ex) {
     Logger.getLogger(ViewPointDao.class.getName()).log(Level.SEVERE, null, ex);
 }
 return false;

}
}</pre>bean：
import java.awt.Image;



public class View {

/**
 * 景點標題
 */
private String title;
/**
 * 景點內容
 */
private String content;
/**
 * 景點圖片
 */
private Image image;

/**
 * 景點圖片上傳路徑
 */
private String imageFile;

/**
 * 分類id
 */
private int catId;

public int getCatId() {
    return catId;
}

public void setCatId(int catId) {
    this.catId = catId;
}

public String getContent() {
    return content;
}

public void setContent(String content) {
    this.content = content;
}

public Image getImage() {
    return image;
}

public void setImage(Image image) {
    this.image = image;
}

public String getTitle() {
    return title;
}

public void setTitle(String title) {
    this.title = title;
}

public String getImageFile() {
    return imageFile;
}

public void setImageFile(String imageFile) {
    this.imageFile = imageFile;
}

}</pre>轉自:http://blog.csdn.net/zhongweijian/article/details/7668930