Hibernate - Saving Image

Often we need to save images or large documents in database. Databases provide saving characters or image files as BLOB (Binary Large Object) or CLOB (Character Large Object). In database, the type is BLOB/LONGBLOB, LONGTEXT etc.

To indicate that an entity has a field that has to be stored as a BLOB,CLOB the @Lob annotation is used. For example, consider the following code snippet −

@Entity
@Table(name = "save_image")
public class LobEntity {

...
   @Lob
   @Column(name = "image") 
   private byte[] image;
...
}

Let's discuss Saving Image in Hibernate in details with an example.

Create Mapping Class

Let's create the POJO class whose data is to be persisted in the database.

LobEntity.java

package com.tutorialspoint;

import javax.persistence.*;

@Entity
@Table(name = "save_image")
public class LobEntity {

   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY) 
   private Long id; 

   public Long getId() {
      return id;
   }

   public void setId(Long id) {
      this.id = id;
   }

   @Lob
   @Column(name = "image") 
   private byte[] image;

   public byte [] getImage() {
      return image;
   }
   public void setImage(byte[] imageData) {
      this.image = imageData;
   }
}

Create Hibernate Configuration File

Now create a hibernate configuration file for database and other details.

hibernate.cfg.xml

<?xml version="1.0" encoding="UTF-8"?>  
<!DOCTYPE hibernate-configuration PUBLIC  
   "-//Hibernate/Hibernate Configuration DTD 5.3//EN"  
   "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">  
<hibernate-configuration>  
   <session-factory>  
      <property name="hbm2ddl.auto">update</property>  
      <property name="dialect">org.hibernate.dialect.MySQL8Dialect</property>  
      <property name="connection.url">jdbc:mysql://localhost/TUTORIALSPOINT</property>  
      <property name="connection.username">root</property>  
      <property name="connection.password">guest123</property>  
      <property name="connection.driver_class">com.mysql.cj.jdbc.Driver</property>  
      <mapping class="com.tutorialspoint.LobEntity"/>  
   </session-factory>  
</hibernate-configuration> 

Notice how in the file mapping element has a class instead of resource. And having hbm2ddl.auto property as update creates the table automatically if table is not present.

Create Application Class

Finally, we will create our application class with the main() method to run the application. We will use this application to test Table per Hiearchy mapping.

SaveBlob.java

package com.tutorialspoint;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.boot.Metadata;
import org.hibernate.boot.MetadataSources;
import org.hibernate.boot.registry.StandardServiceRegistry;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;

import java.io.*;

public class SaveBlob {
   public static void main(String[] args) throws FileNotFoundException, IOException {

      FileInputStream fis = new FileInputStream("C:\\Users\\Saikat\\OneDrive\\Pictures\\almoural_castle.jpg");
      byte[] bytes = new byte[fis.available()];
      StandardServiceRegistry ssr = new StandardServiceRegistryBuilder().configure("hibernate.cfg.xml").build();  
      Metadata meta = new MetadataSources(ssr).getMetadataBuilder().build();  
      SessionFactory factory = meta.getSessionFactoryBuilder().build();  
      Session session = factory.openSession();  
      Transaction t = session.beginTransaction();   
      LobEntity lob = new LobEntity();
      lob.setImage(bytes);
      session.save(lob);
      session.getTransaction().commit();
      fis.close();
      System.out.println("Successfully inserted image in table.");
   }
}

Compilation and Execution

Execute SaveBlob binary to run the program.

Output

You would get the following result, and record would be created in the save_image table.

$java SaveBlob
Successfully inserted image in table.

If you check your save_image table, it should have the following records −

mysql> select id from save_image;
+----+
| id |
+----+
|  1 |
+----+
1 row in set (0.00 sec)


mysql> desc save_image;
+-------+----------+------+-----+---------+----------------+
| Field | Type     | Null | Key | Default | Extra          |
+-------+----------+------+-----+---------+----------------+
| id    | bigint   | NO   | PRI | NULL    | auto_increment |
| image | longblob | YES  |     | NULL    |                |
+-------+----------+------+-----+---------+----------------+
2 rows in set (0.00 sec)