Hibernate + PostgreSQL + Tipo de dirección de red (inet, cdir)

Acabo de resolver un problema como el tuyo. Hay poca información sobre este asunto. Como dijo @ms03... la mejor manera es crear un nuevo tipo y una clase que implemente este tipo y maneje el objeto java para configurar/ingresar a la base de datos.

Primero en su entidad debe declarar tipos para sus parámetros.

@Entity
@Table(name="user_app")
@TypeDefs(value={@TypeDef(name="convertInet",typeClass=PgInetType.class),
         @TypeDef(name="convertMacaddr",typeClass=PgMacaddrType.class)})
public class User implements Serializable {

    //some parameters

  @Type(type="convertMacaddr")
  private PgMacaddr mac;

  @Type(type="convertInet")
  private PgInet ip;

     //getters and setters, equals, hashcode, toString
  }

En segundo lugar, cree el nuevo objeto manejado por Java, debe tener una construcción predeterminada, una construcción para manejar datos de la base de datos y ser serializable.

public class PgInet implements Serializable {

private static final long serialVersionUID = 1L;

private String address;

public PgInet(String address){
    this.address=address;
}

public PgInet(){
    this.address=null;
}

    //Getters,setters,hashcode, equal and toString
 }

Y el paso final debe crear un tipo personalizado

public class PgInetType implements UserType{

@Override
public int[] sqlTypes() {

            //Because inet,macaddr,cdir...and unkwon type for java, yo must
            // define Types.OTHER
    return new int[] { Types.OTHER };
}

@Override
public Class returnedClass() {

            //Object created to be handled for java
    return PgInet.class;
}

@Override
public boolean equals(Object x, Object y) throws HibernateException {
    return ObjectUtils.nullSafeEquals(x, y);
}

@Override
public int hashCode(Object x) throws HibernateException {
    if(x!=null)
        return x.hashCode();
    else
        return 0;
}

@Override
public Object nullSafeGet(ResultSet rs, String[] names,
        SessionImplementor session, Object owner)
        throws HibernateException, SQLException {

            //Translation from DB to Java
    PgInet address=null;

    String ip=rs.getString(names[0]);

    if(ip!=null){
        address=new PgInet(ip);
    }

    return address;
}

@Override
public void nullSafeSet(PreparedStatement st, Object value, int index,
        SessionImplementor session) throws HibernateException, SQLException {

    //Translation from java to DB

    if(value==null){
        st.setNull(index, Types.VARCHAR);
    }else{

                //As inet,macaddr,cdir...are new types object on Postgresql you must
                //create the specific postgresql object and to insert it

                //I created 2 new cast on postgresql: inet As varchar, varchar AS inet
                //but I think it's not neccesary because macaddr type works fine without
                //postgresl casting

        st.setObject(index, getInet(value, st.getConnection()));
    }

}

private Object getInet(Object value, Connection connection) {

           //Expected object on postgresql

       Object tempInet = null;
       ClassLoader connectionClassLoader = connection.getClass().getClassLoader();

       try {

           //Class which will create the postgresql

           Class aPGObjectClass =connectionClassLoader.loadClass("org.postgresql.util.PGobject");
           Constructor ct = aPGObjectClass.getConstructor(null);
           try {
            tempInet = ct.newInstance(null);
        } catch (InstantiationException | IllegalAccessException
                | IllegalArgumentException | InvocationTargetException e2) {
            // TODO Auto-generated catch block
            e2.printStackTrace();
        }

           Method setTypeMethod = aPGObjectClass.getMethod("setType", new Class[]{String.class});
           try {

               //Setting postgresql type, inet in this case

            setTypeMethod.invoke(tempInet, new Object[]{"inet"});
        } catch (IllegalAccessException | IllegalArgumentException
                | InvocationTargetException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }

           Method setValueMethod = aPGObjectClass.getMethod("setValue", new Class[]{String.class});
           try {
            setValueMethod.invoke(tempInet, new Object[]{value.toString()});
        } catch (IllegalAccessException | IllegalArgumentException
                | InvocationTargetException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

       } catch (ClassNotFoundException e) {

       } catch (NoSuchMethodException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (SecurityException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

       return tempInet;
   }

@Override
public Object deepCopy(Object value) throws HibernateException {
    if(value==null)
        return null;
    else{
        PgInet PgInetNew=new PgInet();
        PgInet PgInetOriginal=(PgInet)value;

        PgInetNew.setAddress(PgInetOriginal.getAddress());

        return PgInetNew;
    }
}

@Override
public boolean isMutable() {
    return false;
}

@Override
public Serializable disassemble(Object value) throws HibernateException {
     Object  deepCopy=deepCopy(value);

      if(!(deepCopy instanceof Serializable))
       return (Serializable)deepCopy;

      return null;
}

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

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

 }

De esta manera funciona bien para mí cuando inserto u obtengo una fila de DB.