Hibernate保存图片 文件 到数据库

为了在数据库中保存文件，需要在数据库中定义二进制指端blob. 有的数据库也有 image 类型也可以。在hibernate 实体类 这一边， 定义 类型为 byte[] 就可以。做一个简单的例子测试

1. 在mysql 中创建表

Create TABLE  `yihaomen`.`avatar` (
  `AVATAR_ID` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
  `IMAGE` BLOB NOT NULL,
  PRIMARY KEY (`AVATAR_ID`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

2. 项目所需要的 maven 依赖

  4.0.0
  com.yihaomen.common
  HibernateExample
  jar
  1.0-SNAPSHOT
  HibernateExample
  http://maven.apache.org
  
 
        
               junit
               junit
               3.8.1
               test
        
 
        
	
		mysql
		mysql-connector-java
		5.1.9
	
 
	
	
		hibernate
		hibernate3
		3.2.3.GA
	
 
	
	
		dom4j
		dom4j
		1.6.1
	
 
	
		commons-logging
		commons-logging
		1.1.1
	
 
	
		commons-collections
		commons-collections
		3.2.1
	
 
	
		cglib
		cglib
		2.2
	
	
 
  

3. model 层编写

public class Avatar implements java.io.Serializable {
 
	private Integer avatarId;
	private byte[] image;
 
	public Avatar() {
	}
 
	public Avatar(byte[] image) {
		this.image = image;
	}
 
	public Integer getAvatarId() {
		return this.avatarId;
	}
 
	public void setAvatarId(Integer avatarId) {
		this.avatarId = avatarId;
	}
 
	public byte[] getImage() {
		return this.image;
	}
 
	public void setImage(byte[] image) {
		this.image = image;
	}
 
}

4. Hiberante mapping 配置文件 Avatar.hbm.xml

5. Hibernate 配置文件 hibernate.cfg.xml

    
        false
        com.mysql.jdbc.Driver
        password
        jdbc:mysql://localhost:3306/yihaomen
        root
        org.hibernate.dialect.MySQLDialect
        true
        
    

6. Hibernate 工具类

 
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
 
public class HibernateUtil {
 
    private static final SessionFactory sessionFactory = buildSessionFactory();
 
    private static SessionFactory buildSessionFactory() {
        try {
            // Create the SessionFactory from hibernate.cfg.xml
            return new Configuration().configure().buildSessionFactory();
        }
        catch (Throwable ex) {
            // Make sure you log the exception, as it might be swallowed
            System.err.println("Initial SessionFactory creation failed." + ex);
            throw new ExceptionInInitializerError(ex);
        }
    }
 
    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }
 
    public static void shutdown() {
    	// Close caches and connection pools
    	getSessionFactory().close();
    }
 
}

7. 编写测试代码，并进行测试

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
 
import org.hibernate.Session;
import com.mkyong.persistence.HibernateUtil;
 
public class App 
{
    public static void main( String[] args )
    {
        System.out.println("Hibernate save image into database");
        Session session = HibernateUtil.getSessionFactory().openSession();
 
        session.beginTransaction();
 
        //save image into database
    	File file = new File("C:\\mavan-hibernate-image-mysql.gif");
        byte[] bFile = new byte[(int) file.length()];
 
        try {
	     FileInputStream fileInputStream = new FileInputStream(file);
	     //convert file into array of bytes
	     fileInputStream.read(bFile);
	     fileInputStream.close();
        } catch (Exception e) {
	     e.printStackTrace();
        }
 
        Avatar avatar = new Avatar();
        avatar.setImage(bFile);
 
        session.save(avatar);
 
        //Get image from database
        Avatar avatar2 = (Avatar)session.get(Avatar.class, avatar.getAvatarId());
        byte[] bAvatar = avatar2.getImage();
 
        try{
            FileOutputStream fos = new FileOutputStream("C:\\test.gif"); 
            fos.write(bAvatar);
            fos.close();
        }catch(Exception e){
            e.printStackTrace();
        }
 
        session.getTransaction().commit();
    }
}

由此可见，hibernate 保存文件到数据库，起始并不难，其实就是保存 byte[] , 注意到这点，应该就好处理了。

From：一号门