Blob to String mapping
Hello,
I'm using Hibernate as JPA provider and I'm trying to map clob field form database to String attribute in entity (JPA spec allows this).
Declaration in entity:
@Lob String name;
Declaration in database table:
name varchar(max),
But when I tried to read entity I got following exceptions (depending on jdbc driver I used):
Caused by: com.microsoft.sqlserver.jdbc.SQLServerException: The conversion from varchar to BLOB is unsupported.
at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(SQLServerException.java:170)
at com.microsoft.sqlserver.jdbc.DataTypes.throwConversionError(DataTypes.java:946)
at com.microsoft.sqlserver.jdbc.ServerDTVImpl.getValue(dtv.java:1952)
at com.microsoft.sqlserver.jdbc.DTV.getValue(dtv.java:175)
at com.microsoft.sqlserver.jdbc.Column.getValue(Column.java:113)
at com.microsoft.sqlserver.jdbc.SQLServerResultSet.getValue(SQLServerResultSet.java:1982)
at com.microsoft.sqlserver.jdbc.SQLServerResultSet.getValue(SQLServerResultSet.java:1967)
at com.microsoft.sqlserver.jdbc.SQLServerResultSet.getBlob(SQLServerResultSet.java:2444)
at org.hibernate.type.BlobType.get(BlobType.java:80)
at org.hibernate.type.BlobType.nullSafeGet(BlobType.java:134)
at org.hibernate.loader.hql.QueryLoader.getResultColumnOrRow(QueryLoader.java:356)
at org.hibernate.loader.Loader.getRowFromResultSet(Loader.java:629)
at org.hibernate.loader.Loader.doQuery(Loader.java:724)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
at org.hibernate.loader.Loader.doList(Loader.java:2228)
or
org.hibernate.PropertyAccessException: could not set a field value by reflection setter of model.Entity.name
javax.persistence.PersistenceException: org.hibernate.PropertyAccessException: could not set a field value by reflection setter of model.Entity.name
at org.hibernate.ejb.AbstractEntityManagerImpl.throwPersistenceException(AbstractEntityManagerImpl.java:614)
at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:76)
at TestTest.test3(TestTest.java:66)
Caused by: org.hibernate.PropertyAccessException: could not set a field value by reflection setter of model.Entity.name
at org.hibernate.property.DirectPropertyAccessor$DirectSetter.set(DirectPropertyAccessor.java:114)
at org.hibernate.tuple.entity.AbstractEntityTuplizer.setPropertyValues(AbstractEntityTuplizer.java:360)
at org.hibernate.tuple.entity.PojoEntityTuplizer.setPropertyValues(PojoEntityTuplizer.java:221)
at org.hibernate.persister.entity.AbstractEntityPersister.setPropertyValues(AbstractEntityPersister.java:3594)
at org.hibernate.engine.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:152)
at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:877)
at org.hibernate.loader.Loader.doQuery(Loader.java:752)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
at org.hibernate.loader.Loader.doList(Loader.java:2228)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2125)
at org.hibernate.loader.Loader.list(Loader.java:2120)
at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:401)
at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:361)
at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196)
at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1148)
at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:67)
Caused by: java.lang.IllegalArgumentException: Can not set int field model.Entity.name to org.hibernate.lob.SerializableBlob
at java.lang.reflect.Field.set(Field.java:657)
at org.hibernate.property.DirectPropertyAccessor$DirectSetter.set(DirectPropertyAccessor.java:102)
Which suggests that hibernate doesn't support this mapping. Is it true? Is there any clean solution to this problem or I have to use some kind of workaround?
My environment:
MS SQL Server 2005, Hibernate (3.3.1.GA), JDBC Driver: JTDS (1.2.2) or Microsoft SQL Driver (2.0).
Greetings
Slawek