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Insert the table elements in Collection

开发者 https://www.devze.com 2023-02-02 04:14 出处:网络
HI, I have a collection and i wanna insert all the elements of my table. How i can do this oper开发者_StackOverflow社区ation in EJB QL?

HI,

I have a collection and i wanna insert all the elements of my table.

How i can do this oper开发者_StackOverflow社区ation in EJB QL?

For example: (this isn't my code) I have my Collection:

Collection<Person> coll = new Collectio<Person>

And i have my table Person

@entity
private class Person{

private id;
private name;

//getters setter
}

I have popolate the table and i wanna all the element in my collection.

Thanks.


Introduce Query in your JPA entity:

@Entity
@NamedQuery(name = "Person.findAll", query = "SELECT p from Person p")
public class Person {
  private id;
  private name;

  //getters setter
}

Then inject EntityManager in your code and use query:

public class MyClass {
  @PersistenceUnit(name = "MyEntitiesFromPersistenceXML")
  private EntityManagerFactory emf;

  public void myMethod() {
    EntityManager entityManager = emf.createEntityManager();
    Query query = entityManager.createNamedQuery("Person.findAll");
    @SuppressWarnings("unchecked")
    List<Person> persons = query.getResultList(); 
    // query returns List which, in turn, extends Collection    

  }
}

Btw, why your class is private? It must be public.

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