Blob retrieval in Hibernate 3

jeeves21 · **Joined:** Tue Jan 18, 2005 6:44 pm **Posts:** 39

I have the following mappings in my config file and Im using the ojdbc14.jar and the oci driver for the oracle 10g database.

<property name="hibernate.connection.driver_class">
oracle.jdbc.driver.OracleDriver
</property>
<property name="hibernate.transaction.factory_class">
org.hibernate.transaction.JDBCTransactionFactory
</property>
<property name="hibernate.jdbc.batch_size">0</property>
<property name="hibernate.jdbc.use_streams_for_binary">true</property>

My persistent classes have the following setter and getters

public byte[] getTemplateValue () {
return templateValue;
}

public void setTemplateValue (byte[] templateValue) {
this.templateValue = templateValue;
}

The retrieval returns a larger byte array than what was set using the setter.

In hibernate 3, is there a need to use the BinaryblobType implementation to map the blob objects into a byte[]? The usertype interface has changed since hibernate 2.x so what changes would need to be made to the binaryblobtype implementation?

vinodsingh · **Posted:** Thu Mar 17, 2005 1:10 am

Code:

import java.io.Serializable;
import java.sql.Blob;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;

import org.hibernate.Hibernate;
import org.hibernate.HibernateException;
import org.hibernate.usertype.UserType;

public class BinaryBlobType implements UserType
{
  public int[] sqlTypes()
  {
    return new int[] { Types.BLOB };
  }

  public Class returnedClass()
  {
    return byte[].class;
  }

  public boolean equals(Object x, Object y)
  {
    return (x == y)
        || (x != null && y != null && java.util.Arrays.equals((byte[]) x,
            (byte[]) y));
  }

  public Object nullSafeGet(ResultSet rs, String[] names, Object owner)
      throws HibernateException, SQLException
  {
    Blob blob = rs.getBlob(names[0]);
    if (!rs.wasNull())
      return blob.getBytes(1, (int) blob.length());
    else
      return null;
  }

  public void nullSafeSet(PreparedStatement st, Object value, int index)
      throws HibernateException, SQLException
  {
    if (null == value) 
      st.setNull(index, Types.BLOB); 
    else
      st.setBlob(index, Hibernate.createBlob((byte[]) value));
  }

  public Object deepCopy(Object value)
  {
    if (value == null)
      return null;

    byte[] bytes = (byte[]) value;
    byte[] result = new byte[bytes.length];
    System.arraycopy(bytes, 0, result, 0, bytes.length);

    return result;
  }

  public boolean isMutable()
  {
    return true;
  }

  public int hashCode(Object x) throws HibernateException
  {
    return 0;
  }

  public Serializable disassemble(Object value) throws HibernateException
  {
    return (Serializable)value;
  }

  public Object assemble(Serializable cached, Object owner) throws HibernateException
  {
    return cached;
  }

  public Object replace(Object original, Object target, Object owner) throws HibernateException
  {
    return original; 
  }
}

zet · **Posted:** Tue Apr 26, 2005 7:54 am

I tried that code with Hibernate 3.0.1 and Oracle 10g, but it doesn't work:

Code:

java.lang.ClassCastException
        at oracle.jdbc.driver.OraclePreparedStatement.setBlob(OraclePreparedStatement.java:5730)
        at weblogic.jdbc.wrapper.PreparedStatement.setBlob(PreparedStatement.java:335)
        at util.BinaryBlobType.nullSafeSet(BinaryBlobType.java:50)
        at org.hibernate.type.CustomType.nullSafeSet(CustomType.java:140)
        at org.hibernate.persister.entity.BasicEntityPersister.dehydrate(BasicEntityPersister.java:1626)
        at org.hibernate.persister.entity.BasicEntityPersister.dehydrate(BasicEntityPersister.java:1603)
        at org.hibernate.persister.entity.BasicEntityPersister.insert(BasicEntityPersister.java:1859)
        at org.hibernate.persister.entity.BasicEntityPersister.insert(BasicEntityPersister.java:2209)
        at org.hibernate.action.EntityInsertAction.execute(EntityInsertAction.java:46)
        at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:239)
        at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:223)
        at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:136)
...