How to get Column names of JPA entity

Question

All my JPA entity classes implement an interface called Entity which is defined like this:

public interface Entity extends Serializable {
// some methods

}
         


        

Answer 1

Hibernate can use different naming strategies to map property names, which are defined implicitly (without @Column(name = "...")). To have a 'physical' names you need to dive into Hibernate internals. First, you have to wire an EntityManagerFactory to your service.

@Autowired
private EntityManagerFactory entityManagerFactory;

Second, you have to retrieve an AbstractEntityPersister for your class

    SessionFactory sessionFactory = entityManagerFactory.unwrap(SessionFactory.class);
    AbstractEntityPersister persister = ((AbstractEntityPersister)sessionFactory.getClassMetadata(baseEntity.getClass()));

Third, you're almost there with your code. You just have to handle both cases - with and without @Column annotation. Try this:

for (Field field : baseEntity.getClass().getFields()) {
    if (SecureString.class.isAssignableFrom(field.getType())) {
        String columnName;
        if (field.isAnnotationPresent(Column.class)) {
            columnName = field.getAnnotation(Column.class).name();
        } else {
            String[] columnNames = persister.getPropertyColumnNames(field.getName());
            if (columnNames.length > 0) {
                columnName = columnNames[0];
            }
        }
    }
}

Note that getPropertyColumnNames() retrieves only 'property' fields, that are not a part of primary key. To retrieve key column names, use getKeyColumnNames().

And about id field. Do you really need to have all @Id's in child classes? Maybe would better to move @Id to Entity class and mark this class with @MappedSuperclass annotation? Then you can retrieve it just with baseEntity.getId();