Question

I’m pretty new with hibernate, and I’m trying to transform a JDBC project I have into Hibernate.

I’m using annotations, and I managed to annotate the basic stuff, however, I’m stuck now with the more heavy objects, I don’t know how to annotate them.
Here’s the Class:

@Entity
@Table(name = "person")
public class Person {

    public Person{

    }

    // THIS WILL BE SOON INJECTED BY SPRING
    private static transient PhoneNumberUtil phoneUtil = PhoneNumberUtil.getInstance();
    private static transient EmailValidator validator = EmailValidator.getInstance();

    @Id
    @Column(name = "person_id")
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long id;

    @Column(name = "private_name", nullable = false, length = 20)
    private String privateName;

    @Column(name = "middle_name", length = 20)
    private String middleName;

    @Column(name = "family_name", nullable = false, length = 20)
    private String familyName;

    @Column(name = "age", nullable = false)
    private int age;

    @Column(name = "address1", nullable = false)
    private String address1;

    @Column(name = "address2")
    private String address2;

    //How do I annotate this ? --> Google LIBPHONENUMBER

    private PhoneNumber phone;

    // How do I annotate this ? --> This is a normal PNG image file.
    private File image;

Edit:
The File was previously mapped as a BLOB.
The PhoneNumber was previously persisted as String, and was transformed using the PhoneNumber constructor to Phonenumber.

Answer 1

The other comments about using @Lob are correct for the File type. It is also correct that if you can change the schema to not save the file data in the DB, then you probably should.

To map your PhoneNumber class to a database field, you’re going to need to use a Hibernate custom UserType. It basically tells Hibernate HOW to do the object<–>db mapping for classes that it doesn’t already know about. Telling the PhoneNumber field in Person to use a custom user type is easy:

@Type(type = PhoneNumberType.CLASS_NAME)
@Column
private PhoneNumber phone;

This assumes a very simple one-column storage of the phone number.

To write PhoneNumberType, you’ll need to implement UserType. It looks overwhelming, with the assemble/disassemble/deepCopy, but the main part you care about is nullSetGet/Set, returnedClass and sqlTypes. You’ll end up with some code like this inside your custom type:

@Override
public Class<?> returnedClass() {
    return PhoneNumber.class;
}

@Override
public int[] sqlTypes() {
    return new int[] { Types.VARCHAR };
}

@Override
public Object nullSafeGet(ResultSet rs, String[] names, Object owner) throws HibernateException, SQLException {
    final String value = rs.getString(names[0]);
    return /* PhoneNumber instance created from string. */
}

@Override
public void nullSafeSet(PreparedStatement st, Object value, int index) throws HibernateException, SQLException {
    if (value == null) {
        st.setNull(index, Types.VARBINARY);
        return;
    }

    st.setString(index, ((PhoneNumber) value).toString());
}

You can find plenty of information about how to implement the other methods via google, stackoverflow and the hibernate javadocs. It isn’t that hard to do.

UPDATE: Multi-column user type

Implement CompositeUserType instead of just UserType. There are a few method changes that you care about. First you’ll want to define the multiple property names and types:

public String[] getPropertyNames() {
    return new String[] { "number", "code" };
}

public Type[] getPropertyTypes() {
    return new Type[] { StandardBasicTypes.STRING,
                        StandardBasicTypes.STRING };
}

There’s also getPropertyValue/setPropertyValue to implement. Your nullSafeXxxx implementations would change to read and write two properties instead of one:

@Override
public Object nullSafeGet(ResultSet rs, String[] names, Object owner) throws HibernateException, SQLException {
    // Access column in order defined in getPropertyNames()
    final String number = rs.getString(names[0]);
    final String code = rs.getString(names[1]);
    return /* PhoneNumber instance created from number and country code. */
}