Persisting java objects in oracle blob

Question

I´m having a little problem and may be you can give a hand. What I´m trying to do is to persist any given java object (serializable) into a blob field in database.

The goal: Persist a java object in Oracle Blob

The way: Serializing the object and creating a BlobDomain as part of the entity, mapped to a BLOB field in database

The code:

The Entity:

@Entity
@Table(name = "ARGUMENT")
public class Argument implements java.io.Serializable {
    private static final long   serialVersionUID    = 1L;

    @Id @Column(name = "ID")
    private Long                id;

    @Column(name = "B_VALUE")
    private BlobDomain          value;

...
}

Setting the value:

private void createArgument (Serializable argVal) throws RuntimeException {
    // argVal is the object to be stored
    Argument arg = new Argument();
    byte[] bytes = serialize(argVal);
    BlobDomain value = new BlobDomain(bytes);
    arg.setValue(value);
    argumentDao.persist(arg);
}

public byte[] serialize(Object obj) throws IOException, SerialException, SQLException {
    ByteArrayOutputStream bs = new ByteArrayOutputStream();
    ObjectOutputStream os = new ObjectOutputStream(bs);
    os.writeObject(obj);
    os.close();
    return bs.toByteArray();
}

The error: The Argument entity is being properly sotred in database (ARGUMENT table), but when I try to query any row of the table, it throws the following exception:

org.hibernate.type.SerializationException: could not deserialize

Does anyone has an idea, why is this happening?

Thanks in advance!!

Full stack:

org.hibernate.type.SerializationException: could not deserialize
    at org.hibernate.util.SerializationHelper.deserialize(SerializationHelper.java:188)
    at org.hibernate.util.SerializationHelper.deserialize(SerializationHelper.java:211)
    at org.hibernate.type.SerializableType.fromBytes(SerializableType.java:105)
    at org.hibernate.type.SerializableType.get(SerializableType.java:62)
    at org.hibernate.type.NullableType.nullSafeGet(NullableType.java:184)
    at org.hibernate.type.NullableType.nullSafeGet(NullableType.java:173)
    at org.hibernate.type.AbstractType.hydrate(AbstractType.java:105)
    at org.hibernate.persister.entity.AbstractEntityPersister.hydrate(AbstractEntityPersister.java:2124)
    at org.hibernate.loader.Loader.loadFromResultSet(Loader.java:1404)
    at org.hibernate.loader.Loader.instanceNotYetLoaded(Loader.java:1332)
    at org.hibernate.loader.Loader.getRow(Loader.java:1230)
    at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:603)
    at org.hibernate.loader.Loader.doQuery(Loader.java:724)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
    at org.hibernate.loader.Loader.loadCollection(Loader.java:2015)
    at org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:59)
    at org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:587)
    at org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:83)
    at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1743)
    at org.hibernate.collection.AbstractPersistentCollection.forceInitialization(AbstractPersistentCollection.java:476)
    at org.hibernate.engine.StatefulPersistenceContext.initializeNonLazyCollections(StatefulPersistenceContext.java:867)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:264)
    at org.hibernate.loader.Loader.doList(Loader.java:2228)
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2125)
    at org.hibernate.loader.Loader.list(Loader.java:2120)
    at org.hibernate.hql.classic.QueryTranslatorImpl.list(QueryTranslatorImpl.java:935)
    at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196)
    at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1148)
    at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
    at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:67)
    ... 38 more
Caused by: java.io.StreamCorruptedException: invalid stream header
    at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:764)
    at java.io.ObjectInputStream.<init>(ObjectInputStream.java:277)
    at org.hibernate.util.SerializationHelper$CustomObjectInputStream.<init>(SerializationHelper.java:223)
    at org.hibernate.util.SerializationHelper.deserialize(SerializationHelper.java:180)
    ... 67 more

Answer 1

You need to add annotation

@Lob


import javax.persistence.Lob;

@Column(name = "B_VALUE")
@Lob
private BlobDomain          value;

Also you can define the length of colummn if object is big.

@Column(length = 20971520)

@Lob , Specifies that a persistent property or field should be persisted as a large object to a database-supported large object type.