CODEWITHSUNDEEP
classjpaentity
amitsalyan
amitsalyan

Reputation: 678

How to obtain Class from JPA entity name?

Is there a way to find out the

  java.lang.Class

that is the one having 

@Entity(name = "X")?

In other words use the Entity Name to get the classname of the Entity, of course at runtime :)

Upvotes: 6

Views: 3752

Answers (3)

Petar Tahchiev
Petar Tahchiev

Reputation: 4386

I've raised an issue in the JPA spec to be able to load entity by entity name in 2014:

https://github.com/jakartaee/persistence/issues/85

This was finally implemented seven years later, in 2023. It is currently part of Jakarta Persistence 3.2.0-B02, a prerelease version of the next planned release.

Upvotes: 1

M. Justin
M. Justin

Reputation: 21123

The ability to get an entity by name is being added to the upcoming Jakarta Persistence 3.2 by way of the new Metamodel.entity(String entityName) method.

public static Class<?> getEntityClass(EntityManager entityManager,
                                      String entityName) {
    return entityManager.getMetamodel().entity(entityName).getJavaType();
}

Upvotes: 0

BalusC
BalusC

Reputation: 1108722

All registered @Entitys are available by MetaModel#getEntities(). It returns a List<EntityType<?>> whereby the EntityType has a getName() method representing the @Entity(name) and a getJavaType() representing the associated @Entity class. The MetaModel instance is in turn available by EntityManager#getMetaModel().

In other words, here's the approach in flavor of an utility method:

public static Class<?> getEntityClass(EntityManager entityManager, String entityName) {
    for (EntityType<?> entity : entityManager.getMetamodel().getEntities()) {
        if (entityName.equals(entity.getName())) {
            return entity.getJavaType();
        }
    }

    return null;
}

Upvotes: 8

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