Hi,

This article describes how to map a blob to a byte[] in hibernate 1.3.2.
http://www.hibernate.org/73.html

But I would like to know how to do the same in hibernate 3.

If I just copy the same code in Hibernate 3, it won't compile.
In Hibernate3, the UserType interface has more methods,
e.g. disassembles, assemble() and replace().

Thank you.

To helps others in the future, here is an implementation for Hibernate 3:

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

import org.hibernate.usertype.*;
import org.hibernate.*;

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

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

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

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

public Serializable disassemble(Object value)
{
byte[] bytes = (byte[]) value;
return(bytes);
}

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

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]);
return blob.getBytes(1, (int) blob.length());
}

public void nullSafeSet(PreparedStatement st, Object value, int index)
throws HibernateException, SQLException
{
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;
}
}

With JPA annotations, it's pretty easy. Here's a tutorial on the topic of column mappings:


http://jpa.ezhibernate.com/Javacode/learn.jsp?tutorial=06hibernatetableandcolumnmappingwithjpa